{"id":193,"date":"2026-03-27T17:05:19","date_gmt":"2026-03-27T09:05:19","guid":{"rendered":"https:\/\/codergodv.xyz\/?p=193"},"modified":"2026-03-27T17:05:20","modified_gmt":"2026-03-27T09:05:20","slug":"mysql%e8%a1%a8%e7%9a%84%e5%a2%9e%e5%88%a0%e6%9f%a5%e6%94%b9","status":"publish","type":"post","link":"https:\/\/codergodv.xyz\/index.php\/2026\/03\/27\/mysql%e8%a1%a8%e7%9a%84%e5%a2%9e%e5%88%a0%e6%9f%a5%e6%94%b9\/","title":{"rendered":"MySQL\u8868\u7684\u589e\u5220\u67e5\u6539"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">MySQL\u8868\u7684\u589e\u5220\u6539\u67e5<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8868\u7684\u589e\u5220\u67e5\u6539\u7b80\u79f0CRUD\uff1aCreate\uff08\u65b0\u589e\uff09\uff0cRetrieve\uff08\u67e5\u627e\uff09\uff0cUpdate\uff08\u4fee\u6539\uff09\uff0cDelete\uff08\u5220\u9664\uff09\u3002<\/li>\n\n\n\n<li>CRUD\u7684\u64cd\u4f5c\u5bf9\u8c61\u662f\u5bf9\u8868\u5f53\u4e2d\u7684\u6570\u636e\uff0c\u662f\u5178\u578b\u7684DML\uff08Data Manipulation Language\uff09\u6570\u636e\u64cd\u4f5c\u8bed\u8a00\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Create<\/h3>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u65b0\u589e\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u65b0\u589e\u6570\u636e\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>INSERT &#91;INTO] table_name &#91;(column1 &#91;, column2] ...)] VALUES (value_list1) &#91;, (value_list2)] ...;<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>SQL\u4e2d\u7684\u6bcf\u4e2avalue_list\u90fd\u8868\u793a\u63d2\u5165\u7684\u4e00\u6761\u8bb0\u5f55\uff0c\u6bcf\u4e2avalue_list\u90fd\u7531\u82e5\u5e72\u4e2a\u5f85\u63d2\u5165\u7684\u5217\u503c\u7ec4\u6210\u3002<\/li>\n\n\n\n<li>SQL\u4e2d\u7684column\u5217\u8868\uff0c\u7528\u4e8e\u6307\u5b9a\u6bcf\u4e2avalue_list\u4e2d\u7684\u5404\u4e2a\u5217\u503c\u5e94\u8be5\u63d2\u5165\u5230\u8868\u4e2d\u7684\u54ea\u4e00\u5217\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4e3a\u4e86\u8fdb\u884c\u6f14\u793a\uff0c\u4e0b\u9762\u521b\u5efa\u4e00\u4e2a\u5b66\u751f\u8868\uff0c\u8868\u5f53\u4e2d\u5305\u542b\u81ea\u589e\u957f\u7684\u4e3b\u952eid\u3001\u5b66\u53f7\u3001\u59d3\u540d\u548cQQ\u53f7\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/6a013193068e4927a083dbef38861eb1.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/6a013193068e4927a083dbef38861eb1.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u521b\u5efa\u8868\u5b8c\u6bd5\u540e\u67e5\u770b\u8868\u7ed3\u6784\uff0c\u53ef\u4ee5\u770b\u5230\u8868\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/ef215cb0ce7646c89dba0cdf7a536e2d.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/ef215cb0ce7646c89dba0cdf7a536e2d.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u5355\u884c\u6570\u636e+\u5168\u5217\u63d2\u5165<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5355\u884c\u6570\u636e+\u5168\u5217\u63d2\u5165<\/p>\n<\/blockquote>\n\n\n\n<p>\u4e0b\u9762\u4f7f\u7528insert\u8bed\u53e5\u5411\u5b66\u751f\u8868\u4e2d\u63d2\u5165\u8bb0\u5f55\uff0c\u6bcf\u6b21\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u6761\u8bb0\u5f55\uff0c\u5e76\u4e14\u63d2\u5165\u8bb0\u5f55\u65f6\u4e0d\u6307\u5b9acolumn\u5217\u8868\uff0c\u8868\u793a\u6309\u7167\u8868\u4e2d\u9ed8\u8ba4\u7684\u5217\u987a\u5e8f\u8fdb\u884c\u5168\u5217\u63d2\u5165\uff0c\u56e0\u6b64\u63d2\u5165\u7684\u6bcf\u6761\u8bb0\u5f55\u4e2d\u7684\u5217\u503c\u9700\u8981\u6309\u8868\u5217\u987a\u5e8f\u4f9d\u6b21\u5217\u51fa\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/cd39bfbf7f2f4d7c968991758856b44f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/cd39bfbf7f2f4d7c968991758856b44f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u591a\u884c\u6570\u636e+\u6307\u5b9a\u5217\u63d2\u5165<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u591a\u884c\u6570\u636e+\u6307\u5b9a\u5217\u63d2\u5165<\/p>\n<\/blockquote>\n\n\n\n<p>\u4f7f\u7528insert\u8bed\u53e5\u4e5f\u53ef\u4ee5\u4e00\u6b21\u5411\u8868\u4e2d\u63d2\u5165\u591a\u6761\u8bb0\u5f55\uff0c\u63d2\u5165\u7684\u591a\u6761\u8bb0\u5f55\u4e4b\u95f4\u4f7f\u7528\u9017\u53f7\u9694\u5f00\uff0c\u5e76\u4e14\u63d2\u5165\u8bb0\u5f55\u65f6\u53ef\u4ee5\u53ea\u6307\u5b9a\u67d0\u4e9b\u5217\u8fdb\u884c\u63d2\u5165\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/443e762d23a24de79ad0fd6bec847551.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/443e762d23a24de79ad0fd6bec847551.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> \u5728\u63d2\u5165\u8bb0\u5f55\u65f6\uff0c\u53ea\u6709\u5141\u8bb8\u4e3a\u7a7a\u7684\u5217\u6216\u81ea\u589e\u957f\u53ef\u4ee5\u4e0d\u6307\u5b9a\u503c\u63d2\u5165\uff0c\u4e0d\u5141\u8bb8\u4e3a\u7a7a\u7684\u5217\u5fc5\u987b\u6307\u5b9a\u503c\u63d2\u5165\uff0c\u5426\u5219\u4f1a\u62a5\u9519\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u63d2\u5165\u5426\u5219\u66f4\u65b0<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u63d2\u5165\u5426\u5219\u66f4\u65b0<\/p>\n<\/blockquote>\n\n\n\n<p>\u5411\u8868\u4e2d\u63d2\u5165\u8bb0\u5f55\u65f6\uff0c\u5982\u679c\u5f85\u63d2\u5165\u8bb0\u5f55\u4e2d\u7684\u4e3b\u952e\u6216\u552f\u4e00\u952e\u5df2\u7ecf\u5b58\u5728\uff0c\u90a3\u4e48\u5c31\u4f1a\u56e0\u4e3a\u4e3b\u952e\u51b2\u7a81\u6216\u552f\u4e00\u952e\u51b2\u7a81\u5bfc\u81f4\u63d2\u5165\u5931\u8d25\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/a5f4d92bf2404bd89b92bb13d621b642.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/a5f4d92bf2404bd89b92bb13d621b642.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u8fd9\u65f6\u53ef\u4ee5\u9009\u62e9\u6027\u7684\u8fdb\u884c\u540c\u6b65\u66f4\u65b0\u64cd\u4f5c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u8868\u4e2d\u6ca1\u6709\u51b2\u7a81\u6570\u636e\uff0c\u5219\u76f4\u63a5\u63d2\u5165\u6570\u636e\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u8868\u4e2d\u6709\u51b2\u7a81\u6570\u636e\uff0c\u5219\u5c06\u8868\u4e2d\u7684\u6570\u636e\u8fdb\u884c\u66f4\u65b0\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u63d2\u5165\u5426\u5219\u66f4\u65b0\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>INSERT ... ON DUPLICATE UPDATE column1=value1 &#91;, column2=value2] ...;<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>SQL\u4e2dINSERT\u4e4b\u540e\u8bed\u6cd5\u4e0e\u4e4b\u524d\u7684INSERT\u8bed\u53e5\u76f8\u540c\u3002<\/li>\n\n\n\n<li>UPDATE\u540e\u9762\u7684column=value\uff0c\u8868\u793a\u5f53\u63d2\u5165\u8bb0\u5f55\u51fa\u73b0\u51b2\u7a81\u65f6\u9700\u8981\u66f4\u65b0\u7684\u5217\u503c\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6bd4\u5982\u5411\u5b66\u751f\u8868\u4e2d\u63d2\u5165\u8bb0\u5f55\u65f6\uff0c\u5982\u679c\u6ca1\u6709\u51fa\u73b0\u4e3b\u952e\u51b2\u7a81\u5219\u76f4\u63a5\u63d2\u5165\u8bb0\u5f55\uff0c\u5982\u679c\u51fa\u73b0\u4e86\u4e3b\u952e\u51b2\u7a81\uff0c\u5219\u5c06\u8868\u4e2d\u51b2\u7a81\u8bb0\u5f55\u7684\u5b66\u53f7\u548c\u59d3\u540d\u8fdb\u884c\u66f4\u65b0\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/35a276b05d5d46369901c5e7f206739e.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/35a276b05d5d46369901c5e7f206739e.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u6267\u884c\u63d2\u5165\u5426\u5219\u66f4\u65b0\u7684SQL\u540e\uff0c\u53ef\u4ee5\u901a\u8fc7\u53d7\u5f71\u54cd\u7684\u6570\u636e\u884c\u6570\u6765\u5224\u65ad\u672c\u6b21\u6570\u636e\u7684\u63d2\u5165\u60c5\u51b5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>0 rows affected\uff1a\u8868\u4e2d\u6709\u51b2\u7a81\u6570\u636e\uff0c\u4f46\u51b2\u7a81\u6570\u636e\u7684\u503c\u548c\u6307\u5b9a\u66f4\u65b0\u7684\u503c\u76f8\u540c\u3002<\/li>\n\n\n\n<li>1 row affected\uff1a\u8868\u4e2d\u6ca1\u6709\u51b2\u7a81\u6570\u636e\uff0c\u6570\u636e\u76f4\u63a5\u88ab\u63d2\u5165\u3002<\/li>\n\n\n\n<li>2 rows affected\uff1a\u8868\u4e2d\u6709\u51b2\u7a81\u6570\u636e\uff0c\u5e76\u4e14\u6570\u636e\u5df2\u7ecf\u88ab\u66f4\u65b0\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u66ff\u6362\u6570\u636e<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u66ff\u6362\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u66ff\u6362\u6570\u636e\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u8868\u4e2d\u6ca1\u6709\u51b2\u7a81\u6570\u636e\uff0c\u5219\u76f4\u63a5\u63d2\u5165\u6570\u636e\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u8868\u4e2d\u6709\u51b2\u7a81\u6570\u636e\uff0c\u5219\u5148\u5c06\u8868\u4e2d\u7684\u51b2\u7a81\u6570\u636e\u5220\u9664\uff0c\u7136\u540e\u518d\u63d2\u5165\u6570\u636e\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8981\u8fbe\u5230\u4e0a\u8ff0\u6548\u679c\uff0c\u53ea\u9700\u8981\u5728\u63d2\u5165\u6570\u636e\u65f6\u5c06SQL\u8bed\u53e5\u4e2d\u7684INSERT\u6539\u4e3aREPLACE\u5373\u53ef\u3002\u6bd4\u5982\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8857f6edaa2948d7b51cb166eb9d1957.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8857f6edaa2948d7b51cb166eb9d1957.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u6267\u884c\u66ff\u6362\u6570\u636e\u7684SQL\u540e\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7\u53d7\u5f71\u54cd\u7684\u6570\u636e\u884c\u6570\u6765\u5224\u65ad\u672c\u6b21\u6570\u636e\u7684\u63d2\u5165\u60c5\u51b5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>1 row affected\uff1a\u8868\u4e2d\u6ca1\u6709\u51b2\u7a81\u6570\u636e\uff0c\u6570\u636e\u76f4\u63a5\u88ab\u63d2\u5165\u3002<\/li>\n\n\n\n<li>2 rows affected\uff1a\u8868\u4e2d\u6709\u51b2\u7a81\u6570\u636e\uff0c\u51b2\u7a81\u6570\u636e\u88ab\u5220\u9664\u540e\u91cd\u65b0\u63d2\u5165\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Retrieve<\/h3>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u627e\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u67e5\u627e\u6570\u636e\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT &#91;DISTINCT] {* | {column1 &#91;, column2] ...}} FROM table_name &#91;WHERE ...] &#91;ORDER BY ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>{}\u4e2d\u7684|\u4ee3\u8868\u53ef\u4ee5\u9009\u62e9\u5de6\u4fa7\u7684\u8bed\u53e5\u6216\u53f3\u4fa7\u7684\u8bed\u53e5\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4e3a\u4e86\u8fdb\u884c\u6f14\u793a\uff0c\u4e0b\u9762\u521b\u5efa\u4e00\u4e2a\u6210\u7ee9\u8868\uff0c\u8868\u5f53\u4e2d\u5305\u542b\u81ea\u589e\u957f\u7684\u4e3b\u952eid\u3001\u59d3\u540d\u4ee5\u53ca\u8be5\u540c\u5b66\u7684\u8bed\u6587\u6210\u7ee9\u3001\u6570\u5b66\u6210\u7ee9\u548c\u82f1\u8bed\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/2649bf0e929d47ddb8a956b0c5aea34b.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/2649bf0e929d47ddb8a956b0c5aea34b.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u521b\u5efa\u8868\u5b8c\u6bd5\u540e\u67e5\u770b\u8868\u7ed3\u6784\uff0c\u53ef\u4ee5\u770b\u5230\u8868\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/cd1aa96f1ae246b0848635d70bea0d2c.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/cd1aa96f1ae246b0848635d70bea0d2c.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u63a5\u4e0b\u6765\u5411\u8868\u4e2d\u63d2\u5165\u51e0\u6761\u6d4b\u8bd5\u8bb0\u5f55\uff0c\u4ee5\u4f9b\u6211\u4eec\u8fdb\u884c\u67e5\u627e\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/c9c0f7757dbb4268ab9b36383f42b8b4.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/c9c0f7757dbb4268ab9b36383f42b8b4.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">SELECT \u5217<\/h4>\n\n\n\n<h5 class=\"wp-block-heading\">\u5168\u5217\u67e5\u8be2<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5168\u5217\u67e5\u8be2<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u67e5\u8be2\u6570\u636e\u65f6\u76f4\u63a5\u7528<code>*<\/code>\u4ee3\u66ffcolumn\u5217\u8868\uff0c\u8868\u793a\u8fdb\u884c\u5168\u5217\u67e5\u8be2\uff0c\u8fd9\u65f6\u5c06\u4f1a\u663e\u793a\u88ab\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u7684\u6240\u6709\u5217\u4fe1\u606f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/e4cb5a6a8f0444da9f0e3dacc48cbddb.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/e4cb5a6a8f0444da9f0e3dacc48cbddb.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> \u901a\u5e38\u60c5\u51b5\u4e0b\u4e0d\u5efa\u8bae\u4f7f\u7528<code>*<\/code>\u8fdb\u884c\u5168\u5217\u67e5\u8be2\uff0c\u56e0\u4e3a\u88ab\u67e5\u8be2\u5230\u7684\u6570\u636e\u9700\u8981\u901a\u8fc7\u7f51\u7edc\u4eceMySQL\u670d\u52a1\u5668\u4f20\u8f93\u5230\u672c\u4e3b\u673a\uff0c\u67e5\u8be2\u7684\u5217\u8d8a\u591a\u4e5f\u5c31\u610f\u5473\u7740\u9700\u8981\u4f20\u8f93\u7684\u6570\u636e\u91cf\u8d8a\u5927\uff0c\u6b64\u5916\uff0c\u8fdb\u884c\u5168\u5217\u67e5\u8be2\u8fd8\u53ef\u80fd\u4f1a\u5f71\u54cd\u5230\u7d22\u5f15\u7684\u4f7f\u7528\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u6307\u5b9a\u5217\u67e5\u8be2<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u6307\u5b9a\u5217\u67e5\u8be2<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u67e5\u8be2\u6570\u636e\u65f6\u4e5f\u53ef\u4ee5\u53ea\u5bf9\u6307\u5b9a\u7684\u5217\u8fdb\u884c\u67e5\u8be2\uff0c\u8fd9\u65f6\u5c06\u9700\u8981\u67e5\u8be2\u7684\u5217\u5728column\u5217\u8868\u5217\u51fa\u5373\u53ef\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/1e894d0949a5405c96fa2bddacb7ace4.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/1e894d0949a5405c96fa2bddacb7ace4.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u5b57\u6bb5\u4e3a\u8868\u8fbe\u5f0f<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u5b57\u6bb5\u4e3a\u8868\u8fbe\u5f0f<\/p>\n<\/blockquote>\n\n\n\n<p>\u67e5\u8be2\u6570\u636e\u65f6\uff0ccolumn\u5217\u8868\u4e2d\u9664\u4e86\u80fd\u7f57\u5217\u8868\u4e2d\u5b58\u5728\u7684\u5217\u540d\u5916\uff0c\u6211\u4eec\u4e5f\u53ef\u4ee5\u5c06\u8868\u8fbe\u5f0f\u7f57\u5217\u5230column\u5217\u8868\u4e2d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/b8f4f47574e044fd8919830e3b2538dd.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/b8f4f47574e044fd8919830e3b2538dd.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u56e0\u4e3aselect\u4e0d\u4ec5\u80fd\u591f\u7528\u6765\u67e5\u8be2\u6570\u636e\uff0c\u8fd8\u53ef\u4ee5\u7528\u6765\u8ba1\u7b97\u67d0\u4e9b\u8868\u8fbe\u5f0f\u6216\u6267\u884c\u67d0\u4e9b\u51fd\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/63d663981ed6479abd6bfdfefc038587.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/63d663981ed6479abd6bfdfefc038587.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u5c06\u8868\u8fbe\u5f0f\u7f57\u5217\u5230column\u5217\u8868\uff0c\u90a3\u4e48\u6bcf\u5f53\u4e00\u6761\u8bb0\u5f55\u88ab\u7b5b\u9009\u51fa\u6765\u65f6\u5c31\u4f1a\u6267\u884c\u8fd9\u4e2a\u8868\u8fbe\u5f0f\uff0c\u7136\u540e\u5c06\u8868\u8fbe\u5f0f\u7684\u8ba1\u7b97\u7ed3\u679c\u4f5c\u4e3a\u8fd9\u6761\u8bb0\u5f55\u7684\u4e00\u4e2a\u5217\u503c\u8fdb\u884c\u663e\u793a\u3002<\/p>\n\n\n\n<p>column\u5217\u8868\u4e2d\u7684\u8868\u8fbe\u5f0f\u53ef\u4ee5\u5305\u542b\u8868\u4e2d\u5df2\u6709\u7684\u5b57\u6bb5\uff0c\u8fd9\u65f6\u6bcf\u5f53\u4e00\u6761\u8bb0\u5f55\u88ab\u7b5b\u9009\u51fa\u6765\u65f6\uff0c\u5c31\u4f1a\u5c06\u8bb0\u5f55\u4e2d\u5bf9\u5e94\u7684\u5217\u503c\u63d0\u4f9b\u7ed9\u8868\u8fbe\u5f0f\u8fdb\u884c\u8ba1\u7b97\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/635f8d13059c4487aa04c23c4b301606.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/635f8d13059c4487aa04c23c4b301606.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>column\u5217\u8868\u4e2d\u7684\u8868\u8fbe\u5f0f\u4e2d\u4e5f\u53ef\u4ee5\u5305\u542b\u591a\u4e2a\u8868\u4e2d\u5df2\u6709\u7684\u5b57\u6bb5\uff0c\u8fd9\u65f6\u6211\u4eec\u5c31\u53ef\u4ee5\u901a\u8fc7\u8868\u8fbe\u5f0f\u8ba1\u7b97\u51fa\u66f4\u591a\u6709\u610f\u4e49\u7684\u6570\u636e\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/89553d73bac046dabd7855775be0a1dc.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/89553d73bac046dabd7855775be0a1dc.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u4e3a\u67e5\u8be2\u7ed3\u679c\u6307\u5b9a\u522b\u540d<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u4e3a\u67e5\u8be2\u7ed3\u679c\u6307\u5b9a\u522b\u540d<\/p>\n<\/blockquote>\n\n\n\n<p>\u4e3a\u67e5\u8be2\u7ed3\u679c\u6307\u5b9a\u522b\u540d\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT column &#91;AS] alias_name &#91;...] FROM table_name;<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6bd4\u5982\u67e5\u8be2\u6210\u7ee9\u8868\u4e2d\u7684\u6570\u636e\u65f6\uff0c\u5c06\u6bcf\u6761\u8bb0\u5f55\u4e2d\u7684\u4e09\u79d1\u6210\u7ee9\u76f8\u52a0\uff0c\u7136\u540e\u5c06\u8ba1\u7b97\u7ed3\u679c\u5bf9\u5e94\u7684\u5217\u6307\u5b9a\u522b\u540d\u4e3a\u201c\u603b\u5206\u201d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0b373d3bde734fd2a5f0ba3617bfb734.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0b373d3bde734fd2a5f0ba3617bfb734.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u7ed3\u679c\u53bb\u91cd<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7ed3\u679c\u53bb\u91cd<\/p>\n<\/blockquote>\n\n\n\n<p>\u67e5\u8be2\u6210\u7ee9\u8868\u65f6\u6307\u5b9a\u67e5\u8be2\u6570\u5b66\u6210\u7ee9\u5bf9\u5e94\u7684\u5217\uff0c\u53ef\u4ee5\u770b\u5230\u6570\u5b66\u6210\u7ee9\u4e2d\u6709\u91cd\u590d\u7684\u5206\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/fdbf9c5f1d8d43179dc6fdcbc7662048.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/fdbf9c5f1d8d43179dc6fdcbc7662048.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5982\u679c\u60f3\u8981\u5bf9\u67e5\u8be2\u7ed3\u679c\u8fdb\u884c\u53bb\u91cd\u64cd\u4f5c\uff0c\u53ef\u4ee5\u5728SQL\u4e2d\u7684select\u540e\u9762\u5e26\u4e0adistinct\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8d17c123227848278351481aba76911c.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8d17c123227848278351481aba76911c.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">WHERE \u6761\u4ef6<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>WHERE \u6761\u4ef6<\/p>\n<\/blockquote>\n\n\n\n<p>\u6dfb\u52a0where\u5b50\u53e5\u7684\u533a\u522b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u5728\u67e5\u8be2\u6570\u636e\u65f6\u6ca1\u6709\u6307\u5b9awhere\u5b50\u53e5\uff0c\u90a3\u4e48\u4f1a\u76f4\u63a5\u5c06\u8868\u4e2d\u6240\u6709\u7684\u8bb0\u5f55\u4f5c\u4e3a\u6570\u636e\u6e90\u6765\u4f9d\u6b21\u6267\u884cselect\u8bed\u53e5\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u5728\u67e5\u8be2\u6570\u636e\u65f6\u6307\u5b9a\u4e86where\u5b50\u53e5\uff0c\u90a3\u4e48\u5728\u67e5\u8be2\u6570\u636e\u65f6\u4f1a\u5148\u6839\u636ewhere\u5b50\u53e5\u7b5b\u9009\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\uff0c\u7136\u540e\u5c06\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u4f5c\u4e3a\u6570\u636e\u6e90\u6765\u4f9d\u6b21\u6267\u884cselect\u8bed\u53e5\u3002<\/li>\n<\/ul>\n\n\n\n<p>where\u5b50\u53e5\u4e2d\u53ef\u4ee5\u6307\u660e\u4e00\u4e2a\u6216\u591a\u4e2a\u7b5b\u9009\u6761\u4ef6\uff0c\u5404\u4e2a\u7b5b\u9009\u6761\u4ef6\u4e4b\u95f4\u7528\u903b\u8f91\u8fd0\u7b97\u7b26AND\u6216OR\u8fdb\u884c\u5173\u8054\uff0c\u4e0b\u9762\u7ed9\u51fa\u4e86where\u5b50\u53e5\u4e2d\u5e38\u7528\u7684\u6bd4\u8f83\u8fd0\u7b97\u7b26\u548c\u903b\u8f91\u8fd0\u7b97\u7b26\u3002<\/p>\n\n\n\n<p>\u6bd4\u8f83\u8fd0\u7b97\u7b26\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">\u8fd0\u7b97\u7b26<\/th><th class=\"has-text-align-center\" data-align=\"center\">\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\">&gt;\u3001&gt;=\u3001&lt;\u3001&lt;=<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u5927\u4e8e\u3001\u5927\u4e8e\u7b49\u4e8e\u3001\u5c0f\u4e8e\u3001\u5c0f\u4e8e\u7b49\u4e8e<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">=<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u7b49\u4e8e\u3002NULL\u4e0d\u5b89\u5168\uff0c\u4f8b\u5982NULL=NULL\u7684\u7ed3\u679c\u662fNULL\u800c\u4e0d\u662fTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">&lt;=&gt;<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u7b49\u4e8e\u3002NULL\u5b89\u5168\uff0c\u4f8b\u5982NULL&lt;=&gt;NULL\u7684\u7ed3\u679c\u5c31\u662fTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">!=\u3001&lt;&gt;<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u4e0d\u7b49\u4e8e<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">BETWEEN a0 AND a1<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8303\u56f4\u5339\u914d\u3002\u5982\u679ca0&lt;=value&lt;=a1\uff0c\u5219\u8fd4\u56deTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">IN(option1, option2, \u2026)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u5982\u679c\u662fIN\u4e2d\u7684\u4efb\u610f\u4e00\u4e2aoption\uff0c\u5219\u8fd4\u56deTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">IS NULL<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u5982\u679c\u662fNULL\uff0c\u5219\u8fd4\u56deTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">IS NOT NULL<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u5982\u679c\u4e0d\u662fNULL\uff0c\u5219\u8fd4\u56deTRUE(1)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">LIKE<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u6a21\u7cca\u5339\u914d\u3002%\u8868\u793a\u4efb\u610f\u591a\u4e2a\u5b57\u7b26\uff08\u5305\u62ec0\u4e2a\uff09\uff0c_\u8868\u793a\u4efb\u610f\u4e00\u4e2a\u5b57\u7b26<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u903b\u8f91\u8fd0\u7b97\u7b26\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">\u8fd0\u7b97\u7b26<\/th><th class=\"has-text-align-center\" data-align=\"center\">\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\">AND<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u591a\u4e2a\u6761\u4ef6\u540c\u65f6\u4e3aTRUE(1)\uff0c\u5219\u7ed3\u679c\u4e3aTRUE(1)\uff0c\u5426\u5219\u4e3aFALSE(0)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">OR<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u4efb\u610f\u4e00\u4e2a\u6761\u4ef6\u4e3aTRUE(1)\uff0c\u5219\u7ed3\u679c\u4e3aTRUE(1)\uff0c\u5426\u5219\u4e3aFALSE(0)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">NOT<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u6761\u4ef6\u4e3aTRUE(1)\uff0c\u5219\u7ed3\u679c\u4e3aFALSE(0)\uff1b\u6761\u4ef6\u4e3aFALSE(0)\uff0c\u5219\u7ed3\u679c\u4e3aTRUE(1)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u82f1\u8bed\u4e0d\u53ca\u683c\u7684\u540c\u5b66\u53ca\u5176\u82f1\u8bed\u6210\u7ee9<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u82f1\u8bed\u4e0d\u53ca\u683c\u7684\u540c\u5b66\u53ca\u5176\u82f1\u8bed\u6210\u7ee9<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u82f1\u8bed\u6210\u7ee9\u5c0f\u4e8e60\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u82f1\u8bed\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/35dc58b095f341a48af64fa461f72d6e.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/35dc58b095f341a48af64fa461f72d6e.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u572880\u523090\u5206\u7684\u540c\u5b66\u53ca\u5176\u8bed\u6587\u6210\u7ee9<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u572880\u523090\u5206\u7684\u540c\u5b66\u53ca\u5176\u8bed\u6587\u6210\u7ee9<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u8bed\u6587\u6210\u7ee9\u5927\u4e8e\u7b49\u4e8e80\u5e76\u4e14\u5c0f\u4e8e\u7b49\u4e8e90\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u8bed\u6587\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/7a89b6ee2628430daa31489e9223a46f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/7a89b6ee2628430daa31489e9223a46f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u6b64\u5916\uff0c\u8fd9\u91cc\u4e5f\u53ef\u4ee5\u4f7f\u7528<code>BETWEEN a0 AND a1<\/code>\u6765\u6307\u660e\u8bed\u6587\u6210\u7ee9\u7684\u6240\u5728\u533a\u95f4\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/c4c8f7630667445bb45aa129be1bf7bb.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/c4c8f7630667445bb45aa129be1bf7bb.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u6570\u5b66\u6210\u7ee9\u662f58\u621659\u621698\u621699\u5206\u7684\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u6570\u5b66\u6210\u7ee9\u662f58\u621659\u621698\u621699\u5206\u7684\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u6570\u5b66\u6210\u7ee9\u7b49\u4e8e58\u621659\u621698\u621699\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u6570\u5b66\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/c8a1e0ffa6ac49dea052073f6ccd936a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/c8a1e0ffa6ac49dea052073f6ccd936a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u6b64\u5916\uff0c\u8fd9\u91cc\u4e5f\u53ef\u4ee5\u901a\u8fc7<code>IN(58, 59, 98, 99)<\/code>\u7684\u65b9\u5f0f\u6765\u5224\u65ad\u6570\u5b66\u6210\u7ee9\u662f\u5426\u7b26\u5408\u7b5b\u9009\u8981\u6c42\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/7759a0bb45b84b899359754f7e5521a5.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/7759a0bb45b84b899359754f7e5521a5.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u5206\u522b\u67e5\u8be2\u59d3\u5b59\u7684\u540c\u5b66\u548c\u5b59\u67d0\u540c\u5b66<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u59d3\u5b59\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u901a\u8fc7\u6a21\u7cca\u5339\u914d\u6765\u5224\u65ad\u5f53\u524d\u540c\u5b66\u662f\u5426\u59d3\u5b59\uff08\u9700\u8981\u7528\u5230<code>%<\/code>\u6765\u5339\u914d\u591a\u4e2a\u5b57\u7b26\uff09\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0d21d010c6834f2e899b04b050c775f2.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0d21d010c6834f2e899b04b050c775f2.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u5b59\u67d0\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u901a\u8fc7\u6a21\u7cca\u5339\u914d\u6765\u5224\u65ad\u5f53\u524d\u540c\u5b66\u662f\u5426\u4e3a\u5b59\u67d0\uff08\u9700\u8981\u7528\u5230<code>_<\/code>\u6765\u4e25\u683c\u5339\u914d\u5355\u4e2a\u5b57\u7b26\uff09\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/5e93f97e7ee44e08a2590827fb812a7a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/5e93f97e7ee44e08a2590827fb812a7a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u597d\u4e8e\u82f1\u8bed\u6210\u7ee9\u7684\u540c\u5b66<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u597d\u4e8e\u82f1\u8bed\u6210\u7ee9\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u8bed\u6587\u6210\u7ee9\u5927\u4e8e\u82f1\u8bed\u6210\u7ee9\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u3001\u8bed\u6587\u6210\u7ee9\u548c\u82f1\u8bed\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/603c5a83766f4aa09e857f910e5fd608.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/603c5a83766f4aa09e857f910e5fd608.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u603b\u6210\u7ee9\u5728200\u5206\u4ee5\u4e0b\u7684\u540c\u5b66<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u603b\u6210\u7ee9\u5728200\u5206\u4ee5\u4e0b\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6dfb\u52a0\u8868\u8fbe\u5f0f\u67e5\u8be2\uff0c\u67e5\u8be2\u7684\u8868\u8fbe\u5f0f\u4e3a\u8bed\u6587\u3001\u6570\u5b66\u548c\u82f1\u8bed\u6210\u7ee9\u4e4b\u548c\uff0c\u4e3a\u4e86\u65b9\u4fbf\u89c2\u5bdf\u53ef\u4ee5\u5c06\u8868\u8fbe\u5f0f\u5bf9\u5e94\u7684\u5217\u6307\u5b9a\u522b\u540d\u4e3a\u201c\u603b\u5206\u201d\uff0c\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u4e09\u79d1\u6210\u7ee9\u4e4b\u548c\u5c0f\u4e8e200\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/54cac082cdc8493688fe514ad9f83a71.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/54cac082cdc8493688fe514ad9f83a71.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728where\u5b50\u53e5\u4e2d\u4e0d\u80fd\u4f7f\u7528select\u4e2d\u6307\u5b9a\u7684\u522b\u540d\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u67e5\u8be2\u6570\u636e\u65f6\u662f\u5148\u6839\u636ewhere\u5b50\u53e5\u7b5b\u9009\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002<\/li>\n\n\n\n<li>\u7136\u540e\u518d\u5c06\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u4f5c\u4e3a\u6570\u636e\u6e90\u6765\u4f9d\u6b21\u6267\u884cselect\u8bed\u53e5\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0cwhere\u5b50\u53e5\u7684\u6267\u884c\u662f\u5148\u4e8eselect\u8bed\u53e5\u7684\uff0c\u6240\u4ee5\u5728where\u5b50\u53e5\u4e2d\u4e0d\u80fd\u4f7f\u7528\u522b\u540d\uff0c\u5982\u679c\u5728where\u5b50\u53e5\u4e2d\u4f7f\u7528\u522b\u540d\uff0c\u90a3\u4e48\u5728\u67e5\u8be2\u6570\u636e\u65f6\u5c31\u4f1a\u4ea7\u751f\u62a5\u9519\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0990d27ef1a14f73a8aff96d26dba399.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0990d27ef1a14f73a8aff96d26dba399.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u5927\u4e8e80\u5206\u5e76\u4e14\u4e0d\u59d3\u5b59\u7684\u540c\u5b66<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u8bed\u6587\u6210\u7ee9\u5927\u4e8e80\u5206\u5e76\u4e14\u4e0d\u59d3\u5b59\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u8bed\u6587\u6210\u7ee9\u5927\u4e8e80\uff0c\u5e76\u4e14\u901a\u8fc7\u6a21\u7cca\u5339\u914d\u548cnot\u6765\u4fdd\u8bc1\u8be5\u540c\u5b66\u4e0d\u59d3\u5b59\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u8bed\u6587\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/b518a367cbdd407681991827018df899.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/b518a367cbdd407681991827018df899.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u5b59\u67d0\u540c\u5b66\uff0c\u5426\u5219\u8981\u6c42\u603b\u6210\u7ee9\u5927\u4e8e200\u5206\u5e76\u4e14\u8bed\u6587\u6210\u7ee9\u5c0f\u4e8e\u6570\u5b66\u6210\u7ee9\u5e76\u4e14\u82f1\u8bed\u6210\u7ee9\u5927\u4e8e80\u5206<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u5b59\u67d0\u540c\u5b66\uff0c\u5426\u5219\u8981\u6c42\u603b\u6210\u7ee9\u5927\u4e8e200\u5206\u5e76\u4e14\u8bed\u6587\u6210\u7ee9\u5c0f\u4e8e\u6570\u5b66\u6210\u7ee9\u5e76\u4e14\u82f1\u8bed\u6210\u7ee9\u5927\u4e8e80\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u8be5\u9898\u76ee\u7684\u8981\u6c42\u662f\u67e5\u8be2\u6210\u7ee9\uff0c\u88ab\u67e5\u8be2\u7684\u4eba\u8981\u4e48\u662f\u5b59\u67d0\uff0c\u8981\u4e48\u603b\u6210\u7ee9\u5927\u4e8e200\u5206\u5e76\u4e14\u8bed\u6587\u6210\u7ee9\u5c0f\u4e8e\u6570\u5b66\u6210\u7ee9\u5e76\u4e14\u82f1\u8bed\u6210\u7ee9\u5927\u4e8e80\u5206\uff0c\u67e5\u8be2\u65f6\u9700\u8981\u7528\u5230\u6a21\u7cca\u5339\u914d\u3001\u8868\u8fbe\u5f0f\u67e5\u8be2\u548c\u903b\u8f91\u8fd0\u7b97\u7b26\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/468605e8263a4832b87586e2b1a665da.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/468605e8263a4832b87586e2b1a665da.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">NULL\u7684\u67e5\u8be2<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u51c6\u5907\u6d4b\u8bd5\u8868<\/p>\n<\/blockquote>\n\n\n\n<p>\u8fd9\u91cc\u7528\u4e4b\u524d\u6f14\u793a\u65b0\u589e\u6570\u636e\u7684\u5b66\u751f\u8868\u6765\u6f14\u793aNULL\u67e5\u8be2\uff0c\u5b66\u751f\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/24730ca2da844829bbc34189f0552d78.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/24730ca2da844829bbc34189f0552d78.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2QQ\u53f7\u5df2\u77e5\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3aQQ\u53f7\u4e0d\u4e3aNULL\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548cQQ\u53f7\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/9d4ce7b5c28f478c9d8b2aec2c8bfcb7.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/9d4ce7b5c28f478c9d8b2aec2c8bfcb7.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2QQ\u53f7\u672a\u77e5\u7684\u540c\u5b66<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3aQQ\u53f7\u4e3aNULL\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548cQQ\u53f7\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8bad611d61c54ce790cbf5586588beb7.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8bad611d61c54ce790cbf5586588beb7.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728\u4e0eNULL\u503c\u4f5c\u6bd4\u8f83\u7684\u65f6\u5019\u5e94\u8be5\u4f7f\u7528<code>&lt;=&gt;<\/code>\u8fd0\u7b97\u7b26\uff0c\u4f7f\u7528<code>=<\/code>\u8fd0\u7b97\u7b26\u65e0\u6cd5\u5f97\u5230\u6b63\u786e\u7684\u67e5\u8be2\u7ed3\u679c\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/83b28efe5eb64bef87981b2d1559199a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/83b28efe5eb64bef87981b2d1559199a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u56e0\u4e3a<code>=<\/code>\u8fd0\u7b97\u7b26\u662fNULL\u4e0d\u5b89\u5168\u7684\uff0c\u4f7f\u7528<code>=<\/code>\u8fd0\u7b97\u7b26\u5c06\u4efb\u4f55\u503c\u4e0eNULL\u4f5c\u6bd4\u8f83\uff0c\u5f97\u5230\u7684\u7ed3\u679c\u90fd\u662fNULL\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0d9c073814bd4d088ca6e318fc89fc06.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0d9c073814bd4d088ca6e318fc89fc06.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u4f46\u662f<code>&lt;=&gt;<\/code>\u8fd0\u7b97\u7b26\u662fNULL\u5b89\u5168\u7684\uff0c\u4f7f\u7528<code>&lt;=&gt;<\/code>\u8fd0\u7b97\u7b26\u5c06NULL\u548cNULL\u4f5c\u6bd4\u8f83\u5f97\u5230\u7684\u7ed3\u679c\u4e3aTRUE(1)\uff0c\u5c06\u975eNULL\u503c\u4e0eNULL\u503c\u4f5c\u6bd4\u8f83\u5f97\u5230\u7684\u7ed3\u679c\u4e3aFALSE(0)\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/24ee8587b8874fd6a3e125462c3fb0d5.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/24ee8587b8874fd6a3e125462c3fb0d5.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u7ed3\u679c\u6392\u5e8f<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7ed3\u679c\u6392\u5e8f<\/p>\n<\/blockquote>\n\n\n\n<p>\u7ed3\u679c\u6392\u5e8f\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT ... FROM table_name &#91;WHERE ...] ORDER BY column &#91;ASC | DESC] &#91;, ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>ASC\u548cDESC\u5206\u522b\u4ee3\u8868\u7684\u662f\u6392\u5347\u5e8f\u548c\u6392\u964d\u5e8f\uff0c\u9ed8\u8ba4\u4e3aASC\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u6ce8\u610f\uff1a<\/strong> \u5982\u679c\u67e5\u8be2SQL\u4e2d\u6ca1\u6709order by\u5b50\u53e5\uff0c\u90a3\u4e48\u8fd4\u56de\u7684\u987a\u5e8f\u662f\u672a\u5b9a\u4e49\u7684\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9\uff0c\u6309\u6570\u5b66\u6210\u7ee9\u5347\u5e8f\u663e\u793a<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9\uff0c\u6309\u6570\u5b66\u6210\u7ee9\u5347\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u6570\u5b66\u6210\u7ee9\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167\u6570\u5b66\u6210\u7ee9\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/9bc99152c37045688755120e4fed961d.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/9bc99152c37045688755120e4fed961d.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u540c\u5b66\u53ca\u5176QQ\u53f7\uff0c\u6309QQ\u53f7\u6392\u5e8f\u663e\u793a<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u540c\u5b66\u53ca\u5176QQ\u53f7\uff0c\u6309QQ\u53f7\u5347\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548cQQ\u53f7\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167QQ\u53f7\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/a2013a49519f4d668034cd7108faa9e4.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/a2013a49519f4d668034cd7108faa9e4.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> NULL\u503c\u89c6\u4e3a\u6bd4\u4efb\u4f55\u503c\u90fd\u5c0f\uff0c\u56e0\u6b64\u6392\u5347\u5e8f\u65f6\u51fa\u73b0\u5728\u6700\u4e0a\u9762\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u540c\u5b66\u53ca\u5176QQ\u53f7\uff0c\u6309QQ\u53f7\u964d\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548cQQ\u53f7\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167QQ\u53f7\u8fdb\u884c\u964d\u5e8f\u6392\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/d4943f3c1f104e908839cf6db46cb847.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/d4943f3c1f104e908839cf6db46cb847.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> NULL\u503c\u89c6\u4e3a\u6bd4\u4efb\u4f55\u503c\u90fd\u5c0f\uff0c\u56e0\u6b64\u6392\u964d\u5e8f\u65f6\u51fa\u73b0\u5728\u6700\u4e0b\u9762\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u540c\u5b66\u7684\u5404\u95e8\u6210\u7ee9\uff0c\u4f9d\u6b21\u6309\u6570\u5b66\u964d\u5e8f\u3001\u82f1\u8bed\u5347\u5e8f\u3001\u8bed\u6587\u5347\u5e8f\u663e\u793a<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u540c\u5b66\u7684\u5404\u95e8\u6210\u7ee9\uff0c\u4f9d\u6b21\u6309\u6570\u5b66\u964d\u5e8f\u3001\u82f1\u8bed\u5347\u5e8f\u3001\u8bed\u6587\u5347\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u3001\u6570\u5b66\u6210\u7ee9\u3001\u82f1\u8bed\u6210\u7ee9\u548c\u8bed\u6587\u6210\u7ee9\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u4f9d\u6b21\u6309\u7167\u6570\u5b66\u6210\u7ee9\u6392\u964d\u5e8f\u3001\u82f1\u8bed\u6210\u7ee9\u6392\u5347\u5e8f\u548c\u8bed\u6587\u6210\u7ee9\u6392\u964d\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8f508b39e89444f4aca32a55d1b5240f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8f508b39e89444f4aca32a55d1b5240f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u53ef\u4ee5\u770b\u5230\u663e\u793a\u7ed3\u679c\u662f\u6309\u7167\u6570\u5b66\u6210\u7ee9\u8fdb\u884c\u964d\u5e8f\u6392\u5e8f\u7684\uff0c\u800c\u76f8\u540c\u7684\u6570\u5b66\u6210\u7ee9\u4e4b\u95f4\u5219\u662f\u6309\u7167\u82f1\u8bed\u6210\u7ee9\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f\u7684\u3002<\/p>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>order by\u5b50\u53e5\u4e2d\u53ef\u4ee5\u6307\u660e\u6309\u7167\u591a\u4e2a\u5b57\u6bb5\u8fdb\u884c\u6392\u5e8f\uff0c\u6bcf\u4e2a\u5b57\u6bb5\u90fd\u53ef\u4ee5\u6307\u660e\u6309\u7167\u5347\u5e8f\u6216\u964d\u5e8f\u8fdb\u884c\u6392\u5e8f\uff0c\u5404\u4e2a\u5b57\u6bb5\u4e4b\u95f4\u4f7f\u7528\u9017\u53f7\u9694\u5f00\uff0c\u6392\u5e8f\u4f18\u5148\u7ea7\u4e0e\u4e66\u5199\u987a\u5e8f\u76f8\u540c\u3002<\/li>\n\n\n\n<li>\u6bd4\u5982\u4e0a\u8ff0SQL\u4e2d\uff0c\u5f53\u4e24\u6761\u8bb0\u5f55\u7684\u6570\u5b66\u6210\u7ee9\u76f8\u540c\u65f6\u5c31\u4f1a\u6309\u7167\u82f1\u8bed\u6210\u7ee9\u8fdb\u884c\u6392\u5e8f\uff0c\u5982\u679c\u8fd9\u4e24\u6761\u8bb0\u5f55\u7684\u82f1\u8bed\u6210\u7ee9\u4e5f\u76f8\u540c\u5c31\u4f1a\u7ee7\u7eed\u6309\u7167\u8bed\u6587\u6210\u7ee9\u8fdb\u884c\u6392\u5e8f\uff0c\u4ee5\u6b64\u7c7b\u63a8\u3002<\/li>\n<\/ul>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u540c\u5b66\u53ca\u5176\u603b\u5206\uff0c\u6309\u603b\u5206\u964d\u5e8f\u663e\u793a<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u540c\u5b66\u53ca\u5176\u603b\u5206\uff0c\u6309\u603b\u5206\u964d\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u603b\u5206\uff08\u8868\u8fbe\u5f0f\u67e5\u8be2\uff09\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167\u603b\u5206\u8fdb\u884c\u964d\u5e8f\u6392\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/82e304733314455a983e94f6818da16a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/82e304733314455a983e94f6818da16a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728order by\u5b50\u53e5\u4e2d\u53ef\u4ee5\u4f7f\u7528select\u4e2d\u6307\u5b9a\u7684\u522b\u540d\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u67e5\u8be2\u6570\u636e\u65f6\u662f\u5148\u6839\u636ewhere\u5b50\u53e5\u7b5b\u9009\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002<\/li>\n\n\n\n<li>\u7136\u540e\u518d\u5c06\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u4f5c\u4e3a\u6570\u636e\u6e90\u6765\u4f9d\u6b21\u6267\u884cselect\u8bed\u53e5\u3002<\/li>\n\n\n\n<li>\u6700\u540e\u518d\u901a\u8fc7order by\u5b50\u53e5\u5bf9select\u8bed\u53e5\u7684\u6267\u884c\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0corder by\u5b50\u53e5\u7684\u6267\u884c\u662f\u5728select\u8bed\u53e5\u4e4b\u540e\u7684\uff0c\u6240\u4ee5\u5728order by\u5b50\u53e5\u4e2d\u53ef\u4ee5\u4f7f\u7528\u522b\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/f95e8803defc457990fa9b7c0e2f97bd.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/f95e8803defc457990fa9b7c0e2f97bd.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u67e5\u8be2\u59d3\u5b59\u7684\u540c\u5b66\u6216\u59d3\u66f9\u7684\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9\uff0c\u6309\u6570\u5b66\u6210\u7ee9\u964d\u5e8f\u663e\u793a<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u67e5\u8be2\u59d3\u5b59\u7684\u540c\u5b66\u6216\u59d3\u66f9\u7684\u540c\u5b66\u53ca\u5176\u6570\u5b66\u6210\u7ee9\uff0c\u6309\u6570\u5b66\u6210\u7ee9\u964d\u5e8f\u663e\u793a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5bf9\u4e8e\u8fd9\u79cd\u6bd4\u8f83\u957f\u7684\u9898\u76ee\uff0c\u6211\u4eec\u53ef\u4ee5\u5148\u5bf9\u9898\u76ee\u8fdb\u884c\u5206\u6790\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9898\u76ee\u7684\u524d\u534a\u53e5\u63cf\u8ff0\u7684\u662f\u67e5\u8be2\uff0c\u540e\u534a\u53e5\u63cf\u8ff0\u7684\u662f\u6392\u5e8f\u3002<\/li>\n\n\n\n<li>\u5728\u6392\u5e8f\u7684\u65f6\u5019\u5fc5\u987b\u8981\u6709\u6570\u636e\uff0c\u56e0\u6b64\u53ef\u4ee5\u5148\u5b8c\u6210\u524d\u9762\u7684\u67e5\u8be2\u52a8\u4f5c\uff0c\u7136\u540e\u518d\u6839\u636e\u9898\u76ee\u8981\u6c42\u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u67e5\u8be2\u6570\u636e\u65f6\uff0c\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u59d3\u5b59\u6216\u59d3\u66f9\uff08\u6a21\u7cca\u5339\u914d\uff09\uff0c\u5728select\u7684column\u5217\u8868\u4e2d\u6307\u660e\u8981\u67e5\u8be2\u7684\u5217\u4e3a\u59d3\u540d\u548c\u6570\u5b66\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/908333ea24794a6885b97706d73e528a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/908333ea24794a6885b97706d73e528a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5f53\u67e5\u8be2\u5230\u76ee\u6807\u6570\u636e\u540e\u518d\u5728\u67e5\u8be2SQL\u540e\u6dfb\u52a0order by\u5b50\u53e5\uff0c\u5728order by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167\u6570\u5b66\u6210\u7ee9\u8fdb\u884c\u964d\u5e8f\u6392\u5e8f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/04272c35e88d4faebcc2265b07fe7f78.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/04272c35e88d4faebcc2265b07fe7f78.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b5b\u9009\u5206\u9875\u7ed3\u679c<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7b5b\u9009\u5206\u9875\u7ed3\u679c<\/p>\n<\/blockquote>\n\n\n\n<p>\u4ece\u7b2c0\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fan\u6761\u8bb0\u5f55\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT ... FROM table_name &#91;WHERE ..] &#91;ORDER BY ...] LIMIT n;<\/code><\/pre>\n\n\n\n<p>\u4ece\u7b2cs\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fan\u6761\u8bb0\u5f55\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT ... FROM table_name &#91;WHERE ...] &#91;ORDER BY ...] LIMIT s, n;<\/code><\/pre>\n\n\n\n<p>\u4ece\u7b2cs\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fan\u6761\u8bb0\u5f55\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT ... FROM table_name &#91;WHERE ...] &#91;ORDER BY ...] LIMIT n OFFSET s;<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>\u67e5\u8be2SQL\u4e2d\u5404\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f\u4e3a\uff1awhere\u3001select\u3001order by\u3001limit\u3002<\/li>\n\n\n\n<li>limit\u5b50\u53e5\u5728\u7b5b\u9009\u8bb0\u5f55\u65f6\uff0c\u8bb0\u5f55\u7684\u4e0b\u6807\u4ece0\u5f00\u59cb\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u5efa\u8bae\uff1a<\/strong> \u5bf9\u672a\u77e5\u8868\u8fdb\u884c\u67e5\u8be2\u65f6\u6700\u597d\u5728\u67e5\u8be2SQL\u540e\u52a0\u4e0alimit 1\uff0c\u907f\u514d\u5728\u67e5\u8be2\u5168\u8868\u6570\u636e\u65f6\u56e0\u4e3a\u8868\u4e2d\u6570\u636e\u8fc7\u5927\u800c\u5bfc\u81f4\u6570\u636e\u5e93\u5361\u6b7b\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u6309id\u8fdb\u884c\u5206\u9875\uff0c\u6bcf\u98753\u6761\u8bb0\u5f55\uff0c\u5206\u522b\u663e\u793a\u7b2c1\u30012\u30013\u9875<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u6309id\u8fdb\u884c\u5206\u9875\uff0c\u6bcf\u98753\u6761\u8bb0\u5f55\uff0c\u5206\u522b\u663e\u793a\u7b2c1\u30012\u30013\u9875<\/p>\n<\/blockquote>\n\n\n\n<p>\u8fd9\u91cc\u4f7f\u7528\u6210\u7ee9\u8868\u4e2d\u7684\u6570\u636e\u6765\u6f14\u793a\u5206\u9875\u67e5\u8be2\uff0c\u6210\u7ee9\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/e4cb5a6a8f0444da9f0e3dacc48cbddb-168595802416191.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/e4cb5a6a8f0444da9f0e3dacc48cbddb-168595802416191.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u67e5\u8be2\u7b2c1\u9875\u8bb0\u5f55\u65f6\u5728\u67e5\u8be2\u5168\u8868\u6570\u636e\u7684SQL\u540e\uff0c\u52a0\u4e0alimit\u5b50\u53e5\u6307\u660e\u4ece\u7b2c0\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fa3\u6761\u8bb0\u5f55\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/2e2111e140744158927b7451e5fd7d89.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/2e2111e140744158927b7451e5fd7d89.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u67e5\u8be2\u7b2c2\u9875\u8bb0\u5f55\u65f6\u5728\u67e5\u8be2\u5168\u8868\u6570\u636e\u7684SQL\u540e\uff0c\u52a0\u4e0alimit\u5b50\u53e5\u6307\u660e\u4ece\u7b2c3\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fa3\u6761\u8bb0\u5f55\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/84bac7b5693c4b96a9f5f6070360e122.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/84bac7b5693c4b96a9f5f6070360e122.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u67e5\u8be2\u7b2c3\u9875\u8bb0\u5f55\u65f6\u5728\u67e5\u8be2\u5168\u8868\u6570\u636e\u7684SQL\u540e\uff0c\u52a0\u4e0alimit\u5b50\u53e5\u6307\u660e\u4ece\u7b2c6\u6761\u8bb0\u5f55\u5f00\u59cb\uff0c\u5411\u540e\u7b5b\u9009\u51fa3\u6761\u8bb0\u5f55\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0370266ba86d4dedb9a0426dd74ad4b1.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0370266ba86d4dedb9a0426dd74ad4b1.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> \u5982\u679c\u4ece\u8868\u4e2d\u7b5b\u9009\u51fa\u7684\u8bb0\u5f55\u4e0d\u8db3n\u4e2a\uff0c\u5219\u7b5b\u9009\u51fa\u51e0\u4e2a\u5c31\u663e\u793a\u51e0\u4e2a\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Update<\/h3>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u4fee\u6539\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u4fee\u6539\u6570\u636e\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>UPDATE table_name SET column1=expr1 &#91;, column2=expr2] ... &#91;WHERE ...] &#91;ORDER BY ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>SQL\u4e2d\u7684column=expr\uff0c\u8868\u793a\u5c06\u8bb0\u5f55\u4e2d\u5217\u540d\u4e3acolumn\u7684\u503c\u4fee\u6539\u4e3aexpr\u3002<\/li>\n\n\n\n<li>\u5728\u4fee\u6539\u6570\u636e\u4e4b\u524d\u9700\u8981\u5148\u627e\u5230\u5f85\u4fee\u6539\u7684\u8bb0\u5f55\uff0cupdate\u8bed\u53e5\u4e2d\u7684where\u3001order by\u548climit\u5c31\u662f\u7528\u6765\u5b9a\u4f4d\u6570\u636e\u7684\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u5c06\u5b59\u609f\u7a7a\u540c\u5b66\u7684\u6570\u5b66\u6210\u7ee9\u4fee\u6539\u4e3a80\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5c06\u5b59\u609f\u7a7a\u540c\u5b66\u7684\u6570\u5b66\u6210\u7ee9\u4fee\u6539\u4e3a80\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u4fee\u6539\u6570\u636e\u4e4b\u524d\uff0c\u5148\u67e5\u770b\u5b59\u609f\u7a7a\u540c\u5b66\u5f53\u524d\u7684\u6570\u5b66\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/dde3387192b946ecb22763abcc23b231.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/dde3387192b946ecb22763abcc23b231.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728update\u8bed\u53e5\u4e2d\u6307\u660e\u8981\u5c06\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u7684\u6570\u5b66\u6210\u7ee9\u6539\u4e3a80\u5206\uff0c\u5e76\u5728\u4fee\u6539\u540e\u518d\u6b21\u67e5\u770b\u6570\u636e\u786e\u4fdd\u6570\u636e\u6210\u529f\u88ab\u4fee\u6539\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/5fe9a928675f477782c9f53f167f2237.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/5fe9a928675f477782c9f53f167f2237.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u5c06\u66f9\u5b5f\u5fb7\u540c\u5b66\u7684\u6570\u5b66\u6210\u7ee9\u4fee\u6539\u4e3a60\u5206\uff0c\u8bed\u6587\u6210\u7ee9\u4fee\u6539\u4e3a70\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5c06\u66f9\u5b5f\u5fb7\u540c\u5b66\u7684\u6570\u5b66\u6210\u7ee9\u4fee\u6539\u4e3a60\u5206\uff0c\u8bed\u6587\u6210\u7ee9\u4fee\u6539\u4e3a70\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u4fee\u6539\u6570\u636e\u4e4b\u524d\uff0c\u5148\u67e5\u770b\u66f9\u5b5f\u5fb7\u540c\u5b66\u5f53\u524d\u7684\u6570\u5b66\u6210\u7ee9\u548c\u8bed\u6587\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/4b64b461776247cdb8bc1f917ac0f814.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/4b64b461776247cdb8bc1f917ac0f814.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728update\u8bed\u53e5\u4e2d\u6307\u660e\u8981\u5c06\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u7684\u6570\u5b66\u6210\u7ee9\u6539\u4e3a60\u5206\uff0c\u8bed\u6587\u6210\u7ee9\u6539\u4e3a70\u5206\uff0c\u5e76\u5728\u4fee\u6539\u540e\u518d\u6b21\u67e5\u770b\u6570\u636e\u786e\u4fdd\u6570\u636e\u6210\u529f\u88ab\u4fee\u6539\uff0c\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/f23666ea5bbf4b8cb7188c521d2684b2.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/f23666ea5bbf4b8cb7188c521d2684b2.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u5c06\u603b\u6210\u7ee9\u5012\u6570\u524d\u4e09\u76843\u4f4d\u540c\u5b66\u7684\u6570\u5b66\u6210\u7ee9\u52a0\u4e0a30\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow 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src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728update\u8bed\u53e5\u4e2d\u6307\u660e\u8981\u5c06\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u7684\u6570\u5b66\u6210\u7ee9\u52a0\u4e0a30\u5206\uff0c\u5e76\u5728\u4fee\u6539\u540e\u518d\u6b21\u67e5\u770b\u6570\u636e\u786e\u4fdd\u6570\u636e\u6210\u529f\u88ab\u4fee\u6539\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/4c01bff281fb49f1b78fb310e0dd765f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/4c01bff281fb49f1b78fb310e0dd765f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0cMySQL\u4e2d\u4e0d\u652f\u6301+=\u8fd9\u79cd\u590d\u5408\u8d4b\u503c\u8fd0\u7b97\u7b26\uff0c\u6b64\u5916\uff0c\u8fd9\u91cc\u5728\u67e5\u770b\u66f4\u65b0\u540e\u7684\u6570\u636e\u65f6\u4e0d\u80fd\u67e5\u770b\u603b\u6210\u7ee9\u5012\u6570\u524d\u4e09\u76843\u4f4d\u540c\u5b66\uff0c\u56e0\u4e3a\u4e4b\u524d\u603b\u6210\u7ee9\u5012\u6570\u524d\u4e09\u76843\u4f4d\u540c\u5b66\uff0c\u6570\u5b66\u6210\u7ee9\u52a0\u4e0a30\u5206\u540e\u53ef\u80fd\u5c31\u4e0d\u518d\u662f\u5012\u6570\u524d\u4e09\u4e86\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/3a4905a7cb004a71a6a05d0c0299f717.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/3a4905a7cb004a71a6a05d0c0299f717.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u5c06\u6240\u6709\u540c\u5b66\u7684\u8bed\u6587\u6210\u7ee9\u4fee\u6539\u4e3a\u539f\u6765\u76842\u500d<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5c06\u6240\u6709\u540c\u5b66\u7684\u8bed\u6587\u6210\u7ee9\u4fee\u6539\u4e3a\u539f\u6765\u76842\u500d<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u4fee\u6539\u6570\u636e\u4e4b\u524d\uff0c\u5148\u67e5\u770b\u6240\u6709\u540c\u5b66\u7684\u8bed\u6587\u6210\u7ee9\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/12da2c94d940499a98eb84b3c676c4d3.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/12da2c94d940499a98eb84b3c676c4d3.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728update\u8bed\u53e5\u4e2d\u6307\u660e\u8981\u5c06\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u7684\u8bed\u6587\u6210\u7ee9\u53d8\u4e3a\u539f\u6765\u76842\u500d\uff0c\u5e76\u5728\u4fee\u6539\u540e\u518d\u6b21\u67e5\u770b\u6570\u636e\u786e\u4fdd\u6570\u636e\u6210\u529f\u88ab\u4fee\u6539\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/e1790074af3942d8a79b1ab85ecdec21.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/e1790074af3942d8a79b1ab85ecdec21.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u6ce8\u610f\uff1a<\/strong> \u66f4\u65b0\u5168\u8868\u7684\u8bed\u53e5\u614e\u7528\uff01<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Delete<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">\u5220\u9664\u6570\u636e<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5220\u9664\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u5220\u9664\u6570\u636e\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DELETE FROM table_name &#91;WHERE ...] &#91;ORDER BY ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>\u5728\u5220\u9664\u6570\u636e\u4e4b\u524d\u9700\u8981\u5148\u627e\u5230\u5f85\u5220\u9664\u7684\u8bb0\u5f55\uff0cdelete\u8bed\u53e5\u4e2d\u7684where\u3001order by\u548climit\u5c31\u662f\u7528\u6765\u5b9a\u4f4d\u6570\u636e\u7684\u3002<\/li>\n<\/ul>\n\n\n\n<h5 class=\"wp-block-heading\">\u5220\u9664\u5b59\u609f\u7a7a\u540c\u5b66\u7684\u8003\u8bd5\u6210\u7ee9<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5220\u9664\u5b59\u609f\u7a7a\u540c\u5b66\u7684\u8003\u8bd5\u6210\u7ee9<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u5220\u9664\u6570\u636e\u4e4b\u524d\uff0c\u5148\u67e5\u770b\u5b59\u609f\u7a7a\u540c\u5b66\u7684\u76f8\u5173\u4fe1\u606f\uff0c\u7136\u540e\u5728delete\u8bed\u53e5\u4e2d\u6307\u660e\u5220\u9664\u5b59\u609f\u7a7a\u5bf9\u5e94\u7684\u8bb0\u5f55\uff0c\u5e76\u5728\u5220\u9664\u540e\u518d\u6b21\u67e5\u770b\u6570\u636e\u786e\u4fdd\u6570\u636e\u6210\u529f\u88ab\u5220\u9664\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/418e3c9ca0b144789b13cc6aa7df8287.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/418e3c9ca0b144789b13cc6aa7df8287.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h5 class=\"wp-block-heading\">\u5220\u9664\u6574\u5f20\u8868\u6570\u636e<\/h5>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5220\u9664\u6574\u5f20\u8868\u6570\u636e<\/p>\n<\/blockquote>\n\n\n\n<p>\u521b\u5efa\u4e00\u5f20\u6d4b\u8bd5\u8868\uff0c\u8868\u4e2d\u5305\u542b\u4e00\u4e2a\u81ea\u589e\u957f\u7684\u4e3b\u952eid\u548c\u59d3\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/816480a1a36a4233a423ef8447037872.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/816480a1a36a4233a423ef8447037872.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6d4b\u8bd5\u6570\u636e\u7528\u4e8e\u5220\u9664\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/e32097bbe1f54320ae99665f42f26fc8.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/e32097bbe1f54320ae99665f42f26fc8.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728delete\u8bed\u53e5\u4e2d\u53ea\u6307\u660e\u8981\u5220\u9664\u6570\u636e\u7684\u8868\u540d\uff0c\u800c\u4e0d\u901a\u8fc7where\u3001order by\u548climit\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u65f6\uff0c\u8fd9\u65f6\u5c06\u4f1a\u5220\u9664\u6574\u5f20\u8868\u7684\u6570\u636e\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/7da1470bcf314f1eaf94aa4a2d1c981c.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/7da1470bcf314f1eaf94aa4a2d1c981c.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u518d\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6570\u636e\uff0c\u5728\u63d2\u5165\u6570\u636e\u65f6\u4e0d\u6307\u660e\u81ea\u589e\u957f\u5b57\u6bb5\u7684\u503c\uff0c\u8fd9\u65f6\u4f1a\u53d1\u73b0\u63d2\u5165\u6570\u636e\u5bf9\u5e94\u7684\u81ea\u589e\u957fid\u503c\u662f\u5728\u4e4b\u524d\u7684\u57fa\u7840\u4e0a\u7ee7\u7eed\u589e\u957f\u7684\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/af1c7121120c45ff929487966c444e87.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/af1c7121120c45ff929487966c444e87.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u67e5\u770b\u521b\u5efa\u8868\u65f6\u7684\u76f8\u5173\u4fe1\u606f\u65f6\u53ef\u4ee5\u770b\u5230\uff0c\u6709\u4e00\u4e2a<code>AUTO_INCREMENT=n<\/code>\u7684\u5b57\u6bb5\uff0c\u8be5\u5b57\u6bb5\u8868\u793a\u4e0b\u4e00\u6b21\u63d2\u5165\u6570\u636e\u65f6\u81ea\u589e\u957f\u5b57\u6bb5\u7684\u503c\u5e94\u8be5\u4e3an\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/c78f0e3b2bd44f7fad2899246c916acf.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/c78f0e3b2bd44f7fad2899246c916acf.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5f53\u901a\u8fc7delete\u8bed\u53e5\u5220\u9664\u6574\u8868\u6570\u636e\u65f6\uff0c\u4e0d\u4f1a\u91cd\u7f6e<code>AUTO_INCREMENT=n<\/code>\u5b57\u6bb5\uff0c\u56e0\u6b64\u5220\u9664\u6574\u8868\u6570\u636e\u540e\u63d2\u5165\u6570\u636e\u5bf9\u5e94\u7684\u81ea\u589e\u957fid\u503c\u4f1a\u5728\u539f\u6765\u7684\u57fa\u7840\u4e0a\u7ee7\u7eed\u589e\u957f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8fd617045d134d128ff224a2c9cd490b.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8fd617045d134d128ff224a2c9cd490b.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u6ce8\u610f\uff1a<\/strong> \u5220\u9664\u6574\u8868\u64cd\u4f5c\u8981\u614e\u7528\uff01<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u622a\u65ad\u8868<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u622a\u65ad\u8868<\/p>\n<\/blockquote>\n\n\n\n<p>\u622a\u65ad\u8868\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>TRUNCATE &#91;TABLE] table_name;<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>truncate\u53ea\u80fd\u5bf9\u6574\u8868\u64cd\u4f5c\uff0c\u4e0d\u80fd\u50cfdelete\u4e00\u6837\u9488\u5bf9\u90e8\u5206\u6570\u636e\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li>truncate\u5b9e\u9645\u4e0a\u4e0d\u5bf9\u6570\u636e\u64cd\u4f5c\uff0c\u6240\u4ee5\u6bd4delete\u66f4\u5feb\u3002<\/li>\n\n\n\n<li>truncate\u5728\u5220\u9664\u6570\u636e\u65f6\u4e0d\u7ecf\u8fc7\u771f\u6b63\u7684\u4e8b\u52a1\uff0c\u6240\u4ee5\u65e0\u6cd5\u56de\u6eda\u3002<\/li>\n\n\n\n<li>truncate\u4f1a\u91cd\u7f6e<code>AUTO_INCREMENT=n<\/code>\u5b57\u6bb5\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u521b\u5efa\u4e00\u5f20\u6d4b\u8bd5\u8868\uff0c\u8868\u4e2d\u5305\u542b\u4e00\u4e2a\u81ea\u589e\u957f\u7684\u4e3b\u952eid\u548c\u59d3\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/1d3d5af1c84945feafc2c68ef5c81859.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/1d3d5af1c84945feafc2c68ef5c81859.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6d4b\u8bd5\u6570\u636e\u7528\u4e8e\u5220\u9664\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/4c5dff1c5e4b42ddb802af074ad76727.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/4c5dff1c5e4b42ddb802af074ad76727.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5728truncate\u8bed\u53e5\u4e2d\u53ea\u6307\u660e\u8981\u5220\u9664\u6570\u636e\u7684\u8868\u540d\uff0c\u8fd9\u65f6\u4fbf\u4f1a\u5220\u9664\u6574\u5f20\u8868\u7684\u6570\u636e\uff0c\u4f46\u7531\u4e8etruncate\u5b9e\u9645\u4e0d\u5bf9\u6570\u636e\u64cd\u4f5c\uff0c\u56e0\u6b64\u6267\u884ctruncate\u8bed\u53e5\u540e\u770b\u5230\u5f71\u54cd\u884c\u6570\u4e3a0\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/8d0f127acacd41af9315216e30d62ea3.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/8d0f127acacd41af9315216e30d62ea3.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u518d\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6570\u636e\uff0c\u5728\u63d2\u5165\u6570\u636e\u65f6\u4e0d\u6307\u660e\u81ea\u589e\u957f\u5b57\u6bb5\u7684\u503c\uff0c\u8fd9\u65f6\u4f1a\u53d1\u73b0\u63d2\u5165\u6570\u636e\u5bf9\u5e94\u7684\u81ea\u589e\u957fid\u503c\u662f\u91cd\u65b0\u4ece1\u5f00\u59cb\u589e\u957f\u7684\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0129789fb38945048ee1c7f3b304bca9.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0129789fb38945048ee1c7f3b304bca9.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u67e5\u770b\u521b\u5efa\u8868\u65f6\u7684\u76f8\u5173\u4fe1\u606f\u65f6\u4e5f\u53ef\u4ee5\u770b\u5230\uff0c\u6709\u4e00\u4e2a<code>AUTO_INCREMENT=n<\/code>\u7684\u5b57\u6bb5\uff0c\u8be5\u5b57\u6bb5\u8868\u793a\u4e0b\u4e00\u6b21\u63d2\u5165\u6570\u636e\u65f6\u81ea\u589e\u957f\u5b57\u6bb5\u7684\u503c\u5e94\u8be5\u4e3an\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/e570c4a2b5844048847a6cd938145784.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/e570c4a2b5844048847a6cd938145784.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u4f46\u662f\u5f53\u901a\u8fc7truncate\u8bed\u53e5\u5220\u9664\u6574\u8868\u6570\u636e\u65f6\uff0c\u4f1a\u91cd\u7f6e<code>AUTO_INCREMENT<\/code>\u5b57\u6bb5\uff0c\u56e0\u6b64\u622a\u65ad\u8868\u540e\u63d2\u5165\u6570\u636e\u5bf9\u5e94\u7684\u81ea\u589e\u957fid\u503c\u4f1a\u91cd\u65b0\u4ece1\u5f00\u59cb\u589e\u957f\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/14beb953d78b4274a9db223dbaeda27f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/14beb953d78b4274a9db223dbaeda27f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u6ce8\u610f\uff1a<\/strong> \u622a\u65ad\u8868\u64cd\u4f5c\u8981\u614e\u7528\uff01<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u63d2\u5165\u67e5\u8be2\u7ed3\u679c<\/h3>\n\n\n\n<p>\u63d2\u5165\u67e5\u8be2\u7ed3\u679c\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>INSERT &#91;INTO] table_name &#91;(column1 &#91;, column2] ...)] SELECT ... &#91;WHERE ...] &#91;ORDER BY ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[ ]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>SQL\u7684\u4f5c\u7528\u662f\u5c06\u7b5b\u9009\u51fa\u6765\u7684\u8bb0\u5f55\u63d2\u5165\u5230\u6307\u5b9a\u7684\u8868\u5f53\u4e2d\u3002<\/li>\n\n\n\n<li>SQL\u4e2d\u7684column\uff0c\u8868\u793a\u5c06\u7b5b\u9009\u51fa\u7684\u8bb0\u5f55\u7684\u5404\u4e2a\u5217\u63d2\u5165\u5230\u8868\u4e2d\u7684\u54ea\u4e00\u5217\u3002<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5220\u9664\u8868\u4e2d\u91cd\u590d\u7684\u8bb0\u5f55\uff0c\u91cd\u590d\u7684\u6570\u636e\u53ea\u80fd\u6709\u4e00\u4efd<\/p>\n<\/blockquote>\n\n\n\n<p>\u521b\u5efa\u4e00\u5f20\u6d4b\u8bd5\u8868\uff0c\u8868\u4e2d\u5305\u542bid\u548c\u59d3\u540d\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/90eceef1de8b4cbc87f29ec9de137d6a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/90eceef1de8b4cbc87f29ec9de137d6a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5411\u6d4b\u8bd5\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u6d4b\u8bd5\u6570\u636e\uff0c\u6570\u636e\u4e2d\u5b58\u5728\u91cd\u590d\u7684\u8bb0\u5f55\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/f634ad15c8cc4b40af42d1e1ac4d69f9.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/f634ad15c8cc4b40af42d1e1ac4d69f9.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u73b0\u5728\u8981\u6c42\u5220\u9664\u6d4b\u8bd5\u8868\u4e2d\u91cd\u590d\u7684\u6570\u636e\uff0c\u601d\u8def\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u521b\u5efa\u4e00\u5f20\u4e34\u65f6\u8868\uff0c\u8be5\u8868\u7684\u7ed3\u6784\u4e0e\u6d4b\u8bd5\u8868\u7684\u7ed3\u6784\u76f8\u540c\u3002<\/li>\n\n\n\n<li>\u4ee5\u53bb\u91cd\u7684\u65b9\u5f0f\u67e5\u8be2\u6d4b\u8bd5\u8868\u4e2d\u7684\u6570\u636e\uff0c\u5e76\u5c06\u67e5\u8be2\u7ed3\u679c\u63d2\u5165\u5230\u4e34\u65f6\u8868\u4e2d\u3002<\/li>\n\n\n\n<li>\u5c06\u6d4b\u8bd5\u8868\u91cd\u547d\u540d\u4e3a\u5176\u4ed6\u540d\u5b57\uff0c\u518d\u5c06\u4e34\u65f6\u8868\u91cd\u547d\u540d\u4e3a\u6d4b\u8bd5\u8868\u7684\u540d\u5b57\uff0c\u5b9e\u73b0\u539f\u5b50\u53bb\u91cd\u64cd\u4f5c\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u7531\u4e8e\u4e34\u65f6\u8868\u7684\u7ed3\u6784\u4e0e\u6d4b\u8bd5\u8868\u76f8\u540c\uff0c\u56e0\u6b64\u5728\u521b\u5efa\u4e34\u65f6\u8868\u7684\u65f6\u5019\u53ef\u4ee5\u501f\u52a9like\u8fdb\u884c\u521b\u5efa\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/5f99262f1f6849da9090a3cdf871677d.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/5f99262f1f6849da9090a3cdf871677d.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u901a\u8fc7\u63d2\u5165\u67e5\u8be2\u8bed\u53e5\u5c06\u53bb\u91cd\u67e5\u8be2\u540e\u7684\u7ed3\u679c\u63d2\u5165\u5230\u4e34\u65f6\u8868\u4e2d\uff0c\u7531\u4e8e\u4e34\u65f6\u8868\u548c\u6d4b\u8bd5\u8868\u7684\u7ed3\u6784\u76f8\u540c\uff0c\u5e76\u4e14select\u8fdb\u884c\u7684\u662f\u5168\u5217\u67e5\u8be2\uff0c\u56e0\u6b64\u5728\u63d2\u5165\u65f6\u4e0d\u7528\u5728\u8868\u540d\u540e\u6307\u660ecolumn\u5217\u8868\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/a06309b09aed4316ab097c32e6a16a92.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/a06309b09aed4316ab097c32e6a16a92.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5c06\u6d4b\u8bd5\u8868\u91cd\u547d\u540d\u4e3a\u5176\u4ed6\u540d\u5b57\uff08\u76f8\u5f53\u4e8e\u5bf9\u53bb\u91cd\u524d\u7684\u6570\u636e\u8fdb\u884c\u5907\u4efd\uff0c\u5982\u679c\u4e0d\u9700\u8981\u53ef\u4ee5\u76f4\u63a5\u5220\u9664\uff09\uff0c\u5c06\u4e34\u65f6\u8868\u91cd\u547d\u540d\u4e3a\u6d4b\u8bd5\u8868\u7684\u540d\u5b57\uff0c\u8fd9\u65f6\u4fbf\u5b8c\u6210\u4e86\u8868\u4e2d\u6570\u636e\u7684\u53bb\u91cd\u64cd\u4f5c\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/a7fe63d78a574fa9bc89b6011b502022.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/a7fe63d78a574fa9bc89b6011b502022.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\u805a\u5408\u51fd\u6570<\/h3>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u805a\u5408\u51fd\u6570<\/p>\n<\/blockquote>\n\n\n\n<p>\u805a\u5408\u51fd\u6570\u5bf9\u4e00\u7ec4\u503c\u6267\u884c\u8ba1\u7b97\u5e76\u8fd4\u56de\u5355\u4e00\u7684\u503c\uff0c\u5e38\u7528\u7684\u805a\u5408\u51fd\u6570\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">\u51fd\u6570<\/th><th class=\"has-text-align-center\" data-align=\"center\">\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\">COUNT([DISTINCT] expr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8fd4\u56de\u67e5\u8be2\u5230\u7684\u6570\u636e\u7684\u6570\u91cf<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">SUM([DISTINCT] expr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8fd4\u56de\u67e5\u8be2\u5230\u7684\u6570\u636e\u7684\u603b\u548c\uff0c\u4e0d\u662f\u6570\u5b57\u6ca1\u6709\u610f\u4e49<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">AVG([DISTINCT] expr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8fd4\u56de\u67e5\u8be2\u5230\u7684\u6570\u636e\u7684\u5e73\u5747\u503c\uff0c\u4e0d\u662f\u6570\u5b57\u6ca1\u6709\u610f\u4e49<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">MAX([DISTINCT] expr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8fd4\u56de\u67e5\u8be2\u5230\u7684\u6570\u636e\u7684\u6700\u5927\u503c\uff0c\u4e0d\u662f\u6570\u5b57\u6ca1\u6709\u610f\u4e49<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">MIN([DISTINCT] expr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u8fd4\u56de\u67e5\u8be2\u5230\u7684\u6570\u636e\u7684\u6700\u5c0f\u503c\uff0c\u4e0d\u662f\u6570\u5b57\u6ca1\u6709\u610f\u4e49<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u805a\u5408\u51fd\u6570\u53ef\u4ee5\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528\uff0c\u6b64\u65f6select\u6bcf\u5904\u7406\u4e00\u6761\u8bb0\u5f55\u65f6\u90fd\u4f1a\u5c06\u5bf9\u5e94\u7684\u53c2\u6570\u4f20\u9012\u7ed9\u8fd9\u4e9b\u805a\u5408\u51fd\u6570\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7edf\u8ba1\u73ed\u7ea7\u5171\u6709\u591a\u5c11\u540c\u5b66<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u51c6\u5907\u6d4b\u8bd5\u8868<\/p>\n<\/blockquote>\n\n\n\n<p>\u8fd9\u91cc\u7528\u4e4b\u524d\u7684\u5b66\u751f\u8868\u6765\u8fdb\u884c\u6f14\u793a\uff0c\u5b66\u751f\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/9422bcabac3749efb0cb44edc922f687.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/9422bcabac3749efb0cb44edc922f687.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u4f7f\u7528<code>*<\/code>\u505a\u7edf\u8ba1<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528count\u51fd\u6570\uff0c\u5e76\u5c06<code>*<\/code>\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9count\u51fd\u6570\uff0c\u8fd9\u662f\u4fbf\u80fd\u7edf\u8ba1\u51fa\u8868\u4e2d\u7684\u8bb0\u5f55\u6761\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/c307f200d9454857a1413d8c85e99f6e.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/c307f200d9454857a1413d8c85e99f6e.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u4f7f\u7528\u8868\u8fbe\u5f0f\u505a\u7edf\u8ba1<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528count\u51fd\u6570\uff0c\u5e76\u5c06\u8868\u8fbe\u5f0f\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9count\u51fd\u6570\uff0c\u8fd9\u65f6\u4e5f\u53ef\u4ee5\u7edf\u8ba1\u51fa\u8868\u4e2d\u7684\u8bb0\u5f55\u6761\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/10051aa6fdeb4c4a92039d6ef9eed32a.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/10051aa6fdeb4c4a92039d6ef9eed32a.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u8fd9\u79cd\u5199\u6cd5\u76f8\u5f53\u4e8e\u5728\u67e5\u8be2\u8868\u4e2d\u6570\u636e\u65f6\uff0c\u81ea\u884c\u65b0\u589e\u4e86\u4e00\u5217\u5217\u540d\u4e3a\u7279\u5b9a\u8868\u8fbe\u5f0f\u7684\u5217\uff0c\u6211\u4eec\u5c31\u662f\u5728\u7528count\u51fd\u6570\u7edf\u8ba1\u8be5\u5217\u4e2d\u6709\u591a\u5c11\u4e2a\u6570\u636e\uff0c\u7b49\u4ef7\u4e8e\u7edf\u8ba1\u8868\u4e2d\u6709\u591a\u5c11\u6761\u8bb0\u5f55\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/0edb680a330c4ec38e08a57c0c5261dc.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/0edb680a330c4ec38e08a57c0c5261dc.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u7edf\u8ba1\u73ed\u7ea7\u6536\u96c6\u7684QQ\u53f7\u6709\u591a\u5c11\u4e2a<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u73ed\u7ea7\u6536\u96c6\u7684QQ\u53f7\u6709\u591a\u5c11\u4e2a<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528count\u51fd\u6570\u7edf\u8ba1qq\u5217\u4e2d\u6570\u636e\u7684\u4e2a\u6570\uff0c\u8fd9\u65f6\u4fbf\u80fd\u7edf\u8ba1\u51fa\u8868\u4e2dQQ\u53f7\u7684\u4e2a\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/3bcc5cfae0e846078c5ccadfb9c073d4.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/3bcc5cfae0e846078c5ccadfb9c073d4.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> \u5982\u679ccount\u51fd\u6570\u7684\u53c2\u6570\u662f\u4e00\u4e2a\u786e\u5b9a\u7684\u5217\u540d\uff0c\u90a3\u4e48count\u51fd\u6570\u5c06\u4f1a\u5ffd\u7565\u8be5\u5217\u4e2d\u7684NULL\u503c\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7edf\u8ba1\u672c\u6b21\u8003\u8bd5\u6570\u5b66\u6210\u7ee9\u7684\u5206\u6570\u4e2a\u6570<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u51c6\u5907\u6d4b\u8bd5\u8868<\/p>\n<\/blockquote>\n\n\n\n<p>\u8fd9\u91cc\u7528\u4e4b\u524d\u7684\u6210\u7ee9\u8868\u6765\u8fdb\u884c\u6f14\u793a\uff0c\u6210\u7ee9\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/831961893fc443478b2143570ccb8420.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/831961893fc443478b2143570ccb8420.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u672c\u6b21\u8003\u8bd5\u6570\u5b66\u6210\u7ee9\u7684\u5206\u6570\u4e2a\u6570<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528count\u51fd\u6570\u7edf\u8ba1math\u5217\u4e2d\u6570\u636e\u7684\u4e2a\u6570\uff0c\u8fd9\u65f6\u4fbf\u80fd\u7edf\u8ba1\u51fa\u8868\u4e2d\u7684\u6570\u5b66\u6210\u7ee9\u7684\u4e2a\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/3fa74e0412ad4fbcad555af6d02ed068.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/3fa74e0412ad4fbcad555af6d02ed068.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u672c\u6b21\u8003\u8bd5\u6570\u5b66\u6210\u7ee9\u7684\u5206\u6570\u4e2a\u6570\uff08\u53bb\u91cd\uff09<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728\u4f7f\u7528count\u51fd\u6570\u65f6\uff08\u5305\u62ec\u5176\u4ed6\u805a\u5408\u51fd\u6570\uff09\uff0c\u5728\u4f20\u9012\u7684\u53c2\u6570\u4e4b\u524d\u52a0\u4e0adistinct\uff0c\u8fd9\u65f6\u4fbf\u80fd\u7edf\u8ba1\u51fa\u8868\u4e2d\u6570\u5b66\u6210\u7ee9\u53bb\u91cd\u540e\u7684\u4e2a\u6570\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/4779e15199b0400d87c02bfd945683a3.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/4779e15199b0400d87c02bfd945683a3.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u7edf\u8ba1\u6570\u5b66\u6210\u7ee9\u603b\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u6570\u5b66\u6210\u7ee9\u603b\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528sum\u51fd\u6570\u7edf\u8ba1math\u5217\u4e2d\u6570\u636e\u7684\u603b\u548c\uff0c\u8fd9\u65f6\u4fbf\u80fd\u7edf\u8ba1\u51fa\u8868\u4e2d\u7684\u6570\u5b66\u6210\u7ee9\u7684\u603b\u548c\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/d916dbebb3544c4191e457f316c5c71b.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/d916dbebb3544c4191e457f316c5c71b.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u4e0d\u53ca\u683c\u7684\u6570\u5b66\u6210\u7ee9\u603b\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u6570\u5b66\u6210\u7ee9\u5c0f\u4e8e60\u5206\uff0c\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528sum\u51fd\u6570\u7edf\u8ba1math\u5217\u4e2d\u6570\u636e\u7684\u603b\u548c\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/2bf2c75f672e433090d12206be3af31f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/2bf2c75f672e433090d12206be3af31f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u7531\u4e8e\u5f53\u524d\u6ca1\u6709\u6570\u5b66\u4e0d\u53ca\u683c\u7684\u540c\u5b66\uff0c\u56e0\u6b64\u6c42\u548c\u7ed3\u679c\u4e3aNULL\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7edf\u8ba1\u5e73\u5747\u603b\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u5e73\u5747\u603b\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528avg\u51fd\u6570\u8ba1\u7b97\u603b\u5206\u7684\u5e73\u5747\u503c\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/3de536617c804af3a0723ba1d4165508.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/3de536617c804af3a0723ba1d4165508.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u8fd4\u56de\u82f1\u8bed\u6700\u9ad8\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u8fd4\u56de\u82f1\u8bed\u6700\u9ad8\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528max\u67e5\u8be2\u82f1\u8bed\u6210\u7ee9\u6700\u9ad8\u5206\u3002\u5982\u4e0b\uff1a<br><img decoding=\"async\" src=\"https:\/\/cdn.codergodv.xyz\/084a1f0430fc4e369aa8b17e4796d6d5.png\" alt=\"img\"><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u8fd4\u56de70\u5206\u4ee5\u4e0a\u7684\u82f1\u8bed\u6700\u4f4e\u5206<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u8fd4\u56de70\u5206\u4ee5\u4e0a\u7684\u82f1\u8bed\u6700\u4f4e\u5206<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728where\u5b50\u53e5\u4e2d\u6307\u660e\u7b5b\u9009\u6761\u4ef6\u4e3a\u82f1\u8bed\u6210\u7ee9\u5927\u4e8e70\u5206\uff0c\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528min\u51fd\u6570\u67e5\u8be2\u82f1\u8bed\u6210\u7ee9\u6700\u4f4e\u5206\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/7cf346239eea4eeeb066c0262c1b385f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/7cf346239eea4eeeb066c0262c1b385f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\u5206\u7ec4\u67e5\u8be2<\/h3>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u5206\u7ec4\u67e5\u8be2<\/p>\n<\/blockquote>\n\n\n\n<p>\u5206\u7ec4\u67e5\u8be2\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT column1 &#91;, column2], ... FROM table_name &#91;WHERE ...] GROUP BY column &#91;, ...] &#91;order by ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[ ]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>\u67e5\u8be2SQL\u4e2d\u5404\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f\u4e3a\uff1awhere\u3001group by\u3001select\u3001order by\u3001limit\u3002<\/li>\n\n\n\n<li>group by\u540e\u9762\u7684\u5217\u540d\uff0c\u8868\u793a\u6309\u7167\u6307\u5b9a\u5217\u8fdb\u884c\u5206\u7ec4\u67e5\u8be2\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u5206\u7ec4\u67e5\u8be2\u6d4b\u8bd5\u8868\u2014\u2014\u96c7\u5458\u4fe1\u606f\u8868<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u96c7\u5458\u4fe1\u606f\u8868\u5185\u5bb9<\/p>\n<\/blockquote>\n\n\n\n<p>\u96c7\u5458\u4fe1\u606f\u8868\u4e2d\u5305\u542b\u4e09\u5f20\u8868\uff0c\u5206\u522b\u662f\u5458\u5de5\u8868\uff08emp\uff09\u3001\u90e8\u95e8\u8868\uff08dept\uff09\u548c\u5de5\u8d44\u7b49\u7ea7\u8868\uff08salgrade\uff09\u3002<\/p>\n\n\n\n<p>\u5458\u5de5\u8868\uff08emp\uff09\u5305\u542b\u5982\u4e0b\u5b57\u6bb5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u96c7\u5458\u7f16\u53f7\uff08empno\uff09\u3002<\/li>\n\n\n\n<li>\u96c7\u5458\u59d3\u540d\uff08ename\uff09\u3002<\/li>\n\n\n\n<li>\u96c7\u5458\u804c\u4f4d\uff08job\uff09\u3002<\/li>\n\n\n\n<li>\u96c7\u5458\u9886\u5bfc\u7f16\u53f7\uff08mgr\uff09\u3002<\/li>\n\n\n\n<li>\u96c7\u4f63\u65f6\u95f4\uff08hiredate\uff09\u3002<\/li>\n\n\n\n<li>\u5de5\u8d44\u6708\u85aa\uff08sal\uff09\u3002<\/li>\n\n\n\n<li>\u5956\u91d1\uff08comm\uff09\u3002<\/li>\n\n\n\n<li>\u90e8\u95e8\u7f16\u53f7\uff08deptno\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u90e8\u95e8\u8868\uff08dept\uff09\u4e2d\u5305\u542b\u5982\u4e0b\u5b57\u6bb5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u90e8\u95e8\u7f16\u53f7\uff08deptno\uff09\u3002<\/li>\n\n\n\n<li>\u90e8\u95e8\u540d\u79f0\uff08dname\uff09\u3002<\/li>\n\n\n\n<li>\u90e8\u95e8\u6240\u5728\u5730\u70b9\uff08loc\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u5de5\u8d44\u7b49\u7ea7\u8868\uff08salgrade\uff09\u4e2d\u5305\u542b\u5982\u4e0b\u5b57\u6bb5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b49\u7ea7\uff08grade\uff09\u3002<\/li>\n\n\n\n<li>\u6b64\u7b49\u7ea7\u6700\u4f4e\u5de5\u8d44\uff08losal\uff09\u3002<\/li>\n\n\n\n<li>\u6b64\u7b49\u7ea7\u6700\u9ad8\u5de5\u8d44\uff08hisal\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u96c7\u5458\u4fe1\u606f\u8868SQL<\/p>\n<\/blockquote>\n\n\n\n<p>\u96c7\u5458\u4fe1\u606f\u8868\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP database IF EXISTS `scott`;\nCREATE database IF NOT EXISTS `scott` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;\n\nUSE `scott`;\n\nDROP TABLE IF EXISTS `dept`;\nCREATE TABLE `dept` (\n  `deptno` int(2) unsigned zerofill NOT NULL COMMENT '\u90e8\u95e8\u7f16\u53f7',\n  `dname` varchar(14) DEFAULT NULL COMMENT '\u90e8\u95e8\u540d\u79f0',\n  `loc` varchar(13) DEFAULT NULL COMMENT '\u90e8\u95e8\u6240\u5728\u5730\u70b9'\n);\n\n\nDROP TABLE IF EXISTS `emp`;\nCREATE TABLE `emp` (\n  `empno` int(6) unsigned zerofill NOT NULL COMMENT '\u96c7\u5458\u7f16\u53f7',\n  `ename` varchar(10) DEFAULT NULL COMMENT '\u96c7\u5458\u59d3\u540d',\n  `job` varchar(9) DEFAULT NULL COMMENT '\u96c7\u5458\u804c\u4f4d',\n  `mgr` int(4) unsigned zerofill DEFAULT NULL COMMENT '\u96c7\u5458\u9886\u5bfc\u7f16\u53f7',\n  `hiredate` datetime DEFAULT NULL COMMENT '\u96c7\u4f63\u65f6\u95f4',\n  `sal` decimal(7,2) DEFAULT NULL COMMENT '\u5de5\u8d44\u6708\u85aa',\n  `comm` decimal(7,2) DEFAULT NULL COMMENT '\u5956\u91d1',\n  `deptno` int(2) unsigned zerofill DEFAULT NULL COMMENT '\u90e8\u95e8\u7f16\u53f7'\n);\n\n\nDROP TABLE IF EXISTS `salgrade`;\nCREATE TABLE `salgrade` (\n  `grade` int(11) DEFAULT NULL COMMENT '\u7b49\u7ea7',\n  `losal` int(11) DEFAULT NULL COMMENT '\u6b64\u7b49\u7ea7\u6700\u4f4e\u5de5\u8d44',\n  `hisal` int(11) DEFAULT NULL COMMENT '\u6b64\u7b49\u7ea7\u6700\u9ad8\u5de5\u8d44'\n);\n\n\ninsert into dept (deptno, dname, loc)\nvalues (10, 'ACCOUNTING', 'NEW YORK');\ninsert into dept (deptno, dname, loc)\nvalues (20, 'RESEARCH', 'DALLAS');\ninsert into dept (deptno, dname, loc)\nvalues (30, 'SALES', 'CHICAGO');\ninsert into dept (deptno, dname, loc)\nvalues (40, 'OPERATIONS', 'BOSTON');\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7369, 'SMITH', 'CLERK', 7902, '1980-12-17', 800, null, 20);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7499, 'ALLEN', 'SALESMAN', 7698, '1981-02-20', 1600, 300, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7521, 'WARD', 'SALESMAN', 7698, '1981-02-22', 1250, 500, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7566, 'JONES', 'MANAGER', 7839, '1981-04-02', 2975, null, 20);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7654, 'MARTIN', 'SALESMAN', 7698, '1981-09-28', 1250, 1400, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7698, 'BLAKE', 'MANAGER', 7839, '1981-05-01', 2850, null, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7782, 'CLARK', 'MANAGER', 7839, '1981-06-09', 2450, null, 10);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7788, 'SCOTT', 'ANALYST', 7566, '1987-04-19', 3000, null, 20);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7839, 'KING', 'PRESIDENT', null, '1981-11-17', 5000, null, 10);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7844, 'TURNER', 'SALESMAN', 7698,'1981-09-08', 1500, 0, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7876, 'ADAMS', 'CLERK', 7788, '1987-05-23', 1100, null, 20);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7900, 'JAMES', 'CLERK', 7698, '1981-12-03', 950, null, 30);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7902, 'FORD', 'ANALYST', 7566, '1981-12-03', 3000, null, 20);\n\ninsert into emp (empno, ename, job, mgr, hiredate, sal, comm, deptno)\nvalues (7934, 'MILLER', 'CLERK', 7782, '1982-01-23', 1300, null, 10);\n\ninsert into salgrade (grade, losal, hisal) values (1, 700, 1200);\ninsert into salgrade (grade, losal, hisal) values (2, 1201, 1400);\ninsert into salgrade (grade, losal, hisal) values (3, 1401, 2000);\ninsert into salgrade (grade, losal, hisal) values (4, 2001, 3000);\ninsert into salgrade (grade, losal, hisal) values (5, 3001, 9999);<\/code><\/pre>\n\n\n\n<p>\u4e0a\u8ff0SQL\u4e2d\u521b\u5efa\u4e86\u4e00\u4e2a\u540d\u4e3ascott\u7684\u6570\u636e\u5e93\uff0c\u5728\u8be5\u6570\u636e\u5e93\u4e2d\u5206\u522b\u521b\u5efa\u4e86\u90e8\u95e8\u8868\uff08dept\uff09\u3001\u5458\u5de5\u8868\uff08emp\uff09\u548c\u5de5\u8d44\u7b49\u7ea7\u8868\uff08salgrade\uff09\uff0c\u5e76\u5206\u522b\u5411\u4e09\u5f20\u8868\u4e2d\u63d2\u5165\u4e86\u4e00\u4e9b\u6570\u636e\u7528\u4e8e\u67e5\u8be2\u3002<\/p>\n\n\n\n<p>\u5c06\u4e0a\u8ff0SQL\u4fdd\u5b58\u5230\u6587\u4ef6\u4e2d\uff0c\u7136\u540e\u5728MySQL\u4e2d\u4f7f\u7528source\u547d\u4ee4\u4f9d\u6b21\u6267\u884c\u6587\u4ef6\u4e2d\u7684SQL\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/672eee9eb2b64e99b9e7ee6351f13801.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/672eee9eb2b64e99b9e7ee6351f13801.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u6267\u884c\u5b8c\u6587\u4ef6\u4e2d\u7684SQL\u540e\u67e5\u770b\u6570\u636e\u5e93\uff0c\u5c31\u80fd\u770b\u5230\u591a\u4e86\u4e00\u4e2a\u540d\u4e3ascott\u7684\u6570\u636e\u5e93\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/5c0b212017734cadbed7a25ed614557d.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/5c0b212017734cadbed7a25ed614557d.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u8fdb\u5165\u8be5\u6570\u636e\u5e93\uff0c\u5728\u8be5\u6570\u636e\u5e93\u4e2d\u5c31\u53ef\u4ee5\u770b\u5230\u96c7\u5458\u4fe1\u606f\u8868\u4e2d\u7684\u4e09\u5f20\u8868\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/28762e8ba497487ca6d50b5530a01912.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/28762e8ba497487ca6d50b5530a01912.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5176\u4e2d\u90e8\u95e8\u8868\uff08dept\uff09\u7684\u8868\u7ed3\u6784\u548c\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/b232af400f024f3fb67a28ff3d7205ff.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/b232af400f024f3fb67a28ff3d7205ff.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5458\u5de5\u8868\uff08emp\uff09\u7684\u8868\u7ed3\u6784\u548c\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/4c1752eb1042434dadd0f3f27176b8a4.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/4c1752eb1042434dadd0f3f27176b8a4.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<p>\u5de5\u8d44\u7b49\u7ea7\u8868\uff08salgrade\uff09\u7684\u8868\u7ed3\u6784\u548c\u8868\u4e2d\u7684\u5185\u5bb9\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/050146e3b4f146859253ae951ad7b3ea.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/050146e3b4f146859253ae951ad7b3ea.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"\/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">\u663e\u793a\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u9ad8\u5de5\u8d44<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u663e\u793a\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u9ad8\u5de5\u8d44<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728group by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167\u90e8\u95e8\u53f7\u8fdb\u884c\u5206\u7ec4\uff0c\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528avg\u548cmax\u51fd\u6570\uff0c\u5206\u522b\u67e5\u8be2\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u9ad8\u5de5\u8d44\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/image-20230605233136898.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/image-20230605233136898.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"image-20230605233136898\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong> \u4e0a\u8ff0SQL\u4f1a\u5148\u5c06\u8868\u4e2d\u7684\u6570\u636e\u6309\u7167\u90e8\u95e8\u53f7\u8fdb\u884c\u5206\u7ec4\uff0c\u7136\u540e\u5404\u81ea\u5728\u7ec4\u5185\u505a\u805a\u5408\u67e5\u8be2\u5f97\u5230\u6bcf\u4e2a\u7ec4\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u9ad8\u5de5\u8d44\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u663e\u793a\u6bcf\u4e2a\u90e8\u95e8\u7684\u6bcf\u79cd\u5c97\u4f4d\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u4f4e\u5de5\u8d44<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u663e\u793a\u6bcf\u4e2a\u90e8\u95e8\u7684\u6bcf\u79cd\u5c97\u4f4d\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u4f4e\u5de5\u8d44<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728group by\u5b50\u53e5\u4e2d\u6307\u660e\u4f9d\u6b21\u6309\u7167\u90e8\u95e8\u53f7\u548c\u5c97\u4f4d\u8fdb\u884c\u5206\u7ec4\uff0c\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528avg\u51fd\u6570\u548cmin\u51fd\u6570\uff0c\u5206\u522b\u67e5\u8be2\u6bcf\u4e2a\u90e8\u95e8\u7684\u6bcf\u79cd\u5c97\u4f4d\u7684\u5e73\u5747\u5de5\u8d44\u548c\u6700\u4f4e\u5de5\u8d44\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/image-20230605233816225.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/cdn.codergodv.xyz\/image-20230605233816225.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"image-20230605233816225\"\/><\/div><\/figure>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>group by\u5b50\u53e5\u4e2d\u53ef\u4ee5\u6307\u660e\u6309\u7167\u591a\u4e2a\u5b57\u6bb5\u8fdb\u884c\u5206\u7ec4\uff0c\u5404\u4e2a\u5b57\u6bb5\u4e4b\u95f4\u4f7f\u7528\u9017\u53f7\u9694\u5f00\uff0c\u5206\u7ec4\u4f18\u5148\u7ea7\u4e0e\u4e66\u5199\u987a\u5e8f\u76f8\u540c\u3002<\/li>\n\n\n\n<li>\u6bd4\u5982\u4e0a\u8ff0SQL\u4e2d\uff0c\u5f53\u4e24\u6761\u8bb0\u5f55\u7684\u90e8\u95e8\u53f7\u76f8\u540c\u65f6\uff0c\u5c06\u4f1a\u7ee7\u7eed\u6309\u7167\u5c97\u4f4d\u8fdb\u884c\u5206\u7ec4\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">HAVING \u6761\u4ef6<\/h4>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>HAVING \u6761\u4ef6<\/p>\n<\/blockquote>\n\n\n\n<p>\u542b\u6709having\u5b50\u53e5\u7684SQL\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT ... FROM table_name &#91;WHERE ...] &#91;GROUP BY ...] &#91;HAVING ...] &#91;order by ...] &#91;LIMIT ...];<\/code><\/pre>\n\n\n\n<p><strong>\u8bf4\u660e\u4e00\u4e0b\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SQL\u4e2d\u5927\u5199\u7684\u8868\u793a\u5173\u952e\u5b57\uff0c[ ]\u4e2d\u4ee3\u8868\u7684\u662f\u53ef\u9009\u9879\u3002<\/li>\n\n\n\n<li>SQL\u4e2d\u5404\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f\u4e3a\uff1awhere\u3001group by\u3001select\u3001having\u3001order by\u3001limit\u3002<\/li>\n\n\n\n<li>having\u5b50\u53e5\u4e2d\u53ef\u4ee5\u6307\u660e\u4e00\u4e2a\u6216\u591a\u4e2a\u7b5b\u9009\u6761\u4ef6\u3002<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>SQL\u4e2d\u5404\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f<\/p>\n<\/blockquote>\n\n\n\n<p>\u67e5\u8be2\u6570\u636e\u65f6\uff0cSQL\u4e2d\u5404\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6839\u636ewhere\u5b50\u53e5\u7b5b\u9009\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002<\/li>\n\n\n\n<li>\u6839\u636egroup by\u5b50\u53e5\u5bf9\u6570\u636e\u8fdb\u884c\u5206\u7ec4\u3002<\/li>\n\n\n\n<li>\u5c06\u5206\u7ec4\u540e\u7684\u6570\u636e\u56e0\u6b64\u6267\u884cselect\u8bed\u53e5\u3002<\/li>\n\n\n\n<li>\u6839\u636ehaving\u5b50\u53e5\u5bf9\u5206\u7ec4\u540e\u7684\u6570\u636e\u8fdb\u884c\u8fdb\u4e00\u6b65\u7b5b\u9009\u3002<\/li>\n\n\n\n<li>\u6839\u636eorder by\u5b50\u53e5\u5bf9\u6570\u636e\u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n\n\n\n<li>\u6839\u636elimit\u5b50\u53e5\u7b5b\u9009\u82e5\u5e72\u6761\u8bb0\u5f55\u8fdb\u884c\u663e\u793a\u3002<\/li>\n<\/ol>\n\n\n\n<h5 class=\"wp-block-heading\">\u663e\u793a\u5e73\u5747\u5de5\u8d44\u4f4e\u4e8e2000\u7684\u90e8\u95e8\u548c\u5b83\u7684\u5e73\u5747\u5de5\u8d44<\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5148\u7edf\u8ba1\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\u3002<\/li>\n\n\n\n<li>\u7136\u540e\u901a\u8fc7having\u5b50\u53e5\u7b5b\u9009\u51fa\u5e73\u5747\u5de5\u8d44\u4f4e\u4e8e2000\u7684\u90e8\u95e8\u3002<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u7edf\u8ba1\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44<\/p>\n<\/blockquote>\n\n\n\n<p>\u5728group by\u5b50\u53e5\u4e2d\u6307\u660e\u6309\u7167\u90e8\u95e8\u53f7\u8fdb\u884c\u5206\u7ec4\uff0c\u5728select\u8bed\u53e5\u4e2d\u4f7f\u7528avg\u51fd\u6570\u67e5\u8be2\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\u3002\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/cdn.codergodv.xyz\/image-20230605235320729.png'><img class=\"lazyload lazyload-style-1\" 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