{"id":18959,"date":"2025-08-08T12:48:44","date_gmt":"2025-08-08T04:48:44","guid":{"rendered":"https:\/\/92it.top\/?p=18959"},"modified":"2025-08-08T12:48:44","modified_gmt":"2025-08-08T04:48:44","slug":"%e5%9c%a8%e5%81%9asql%e6%80%a7%e8%83%bd%e8%b0%83%e4%bc%98%e7%9a%84%e6%97%b6%e5%80%99%e5%a6%82%e4%bd%95%e7%b2%be%e5%87%86%e5%ae%9a%e4%bd%8d%e5%b9%b6%e8%a7%a3%e5%86%b3%e9%97%ae%e9%a2%98%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=18959","title":{"rendered":"\u5728\u505aSQL\u6027\u80fd\u8c03\u4f18\u7684\u65f6\u5019\u5982\u4f55\u7cbe\u51c6\u5b9a\u4f4d\u5e76\u89e3\u51b3\u95ee\u9898\uff1f"},"content":{"rendered":"\n<p>\u8f6c\u8f7d\uff1a<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/sql_optimization.html#_1-%E6%95%B0%E6%8D%AE%E5%BA%93%E6%80%A7%E8%83%BD%E4%BC%98%E5%8C%96%E6%A0%B8%E5%BF%83%E8%A6%81%E7%82%B9\">\u5728\u505aSQL\u6027\u80fd\u8c03\u4f18\u7684\u65f6\u5019\u5982\u4f55\u7cbe\u51c6\u5b9a\u4f4d\u5e76\u89e3\u51b3\u95ee\u9898<\/a><\/p>\n\n\n\n<p>\u4eca\u5929\u60f3\u548c\u5927\u5bb6\u6df1\u5165\u804a\u804a\u6570\u636e\u5e93\u6027\u80fd\u4f18\u5316\u4e2d\u4e00\u4e2a\u7ed5\u4e0d\u5f00\u7684\u8bdd\u9898\u2014\u2014SQL\u4f18\u5316\u3002\u79c0\u624d\u5728\u540e\u7aef\u67b6\u6784\u9886\u57df\u6df1\u8015\u591a\u5e74\uff0c\u53d1\u73b0\u65e0\u8bba\u6280\u672f\u6f6e\u6d41\u5982\u4f55\u6f14\u53d8\uff0c\u5bf9\u7cfb\u7edf\u6027\u80fd\u7684\u6781\u81f4\u8ffd\u6c42\u59cb\u7ec8\u662f\u8861\u91cf\u4e00\u4f4d\u5de5\u7a0b\u5e08\u6280\u672f\u6df1\u5ea6\u4e0e\u5e7f\u5ea6\u7684\u6838\u5fc3\u6807\u51c6\u3002\u5728\u9762\u8bd5\u4e2d\uff0c\u5982\u679c\u4f60\u80fd\u5c55\u73b0\u51fa\u5bf9\u6027\u80fd\u4f18\u5316\u7684\u6df1\u523b\u7406\u89e3\u548c\u5b9e\u8df5\u7ecf\u9a8c\uff0c\u65e0\u7591\u4f1a\u662f\u4e00\u4e2a\u5de8\u5927\u7684\u52a0\u5206\u9879\u3002\u9ad8\u5e76\u53d1\u9879\u76ee\u7684\u7ecf\u9a8c\u6216\u8bb8\u4e0d\u662f\u4eba\u4eba\u90fd\u6709\u673a\u4f1a\u63a5\u89e6\u3002\u76f8\u6bd4\u4e4b\u4e0b\uff0c\u6027\u80fd\u4f18\u5316\uff0c\u5c24\u5176\u662f\u6570\u636e\u5e93\u5c42\u9762\u7684\u6027\u80fd\u4f18\u5316\uff0c\u662f\u4e00\u9879\u6211\u4eec\u80fd\u4e3b\u52a8\u5b66\u4e60\u3001\u5b9e\u8df5\u5e76\u80fd\u521b\u9020\u5de8\u5927\u4ef7\u503c\u7684\u786c\u6838\u6280\u80fd\u3002<\/p>\n\n\n\n<p>\u5728\u4f17\u591a\u6027\u80fd\u4f18\u5316\u624b\u6bb5\u4e2d\uff0cSQL\u4f18\u5316\u662f\u6700\u76f4\u63a5\u3001\u6700\u5e38\u89c1\u7684\u5207\u5165\u70b9\u3002\u4e00\u4e2a\u5fae\u5c0f\u7684\u6539\u52a8\uff0c\u53ef\u80fd\u5e26\u6765\u6570\u5341\u751a\u81f3\u4e0a\u767e\u500d\u7684\u6027\u80fd\u63d0\u5347\u3002\u90a3\u4e48\uff0c\u5982\u4f55\u7cfb\u7edf\u5730\u8fdb\u884cSQL\u4f18\u5316\u5462\uff1f\u6211\u4eec\u4e00\u6b65\u6b65\u6765\u770b<\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>1. \u6570\u636e\u5e93\u6027\u80fd\u4f18\u5316\u6838\u5fc3\u8981\u70b9<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u5728\u7740\u624b\u4f18\u5316\u5177\u4f53\u7684SQL\u8bed\u53e5\u4e4b\u524d\uff0c\u6211\u4eec\u5fc5\u987b\u5148\u5efa\u7acb\u4e00\u4e2a\u5168\u5c40\u89c6\u91ce\uff0c\u660e\u786eSQL\u4f18\u5316\u5728\u6574\u4e2a\u6570\u636e\u5e93\u6027\u80fd\u4f53\u7cfb\u4e2d\u6240\u5904\u7684\u4f4d\u7f6e\u3002\u6211\u4eec\u53ef\u4ee5\u5c06\u6570\u636e\u5e93\u4f18\u5316\u60f3\u8c61\u6210\u4e00\u4e2a\u5c42\u7ea7\u5206\u660e\u7684\u91d1\u5b57\u5854\u7ed3\u6784\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>\u786c\u4ef6\u5c42\u4f18\u5316<\/strong>\uff1a\u4f4d\u4e8e\u91d1\u5b57\u5854\u7684\u57fa\u5ea7\uff0c\u4e5f\u662f\u6700\u57fa\u7840\u7684\u4f18\u5316\u624b\u6bb5\u3002\u5b83\u6d89\u53ca\u63d0\u5347\u7269\u7406\u8d44\u6e90\u7684\u89c4\u683c\uff0c\u4f8b\u5982\u91c7\u7528\u66f4\u9ad8\u4e3b\u9891\u7684CPU\u3001\u6269\u5c55\u5185\u5b58\u5bb9\u91cf\u3001\u6216\u7528NVMe SSD\u66ff\u6362\u4f20\u7edf\u786c\u76d8\u3002<\/li>\n\n\n\n<li><strong>\u7cfb\u7edf\u5c42\u4f18\u5316<\/strong>\uff1a\u5728\u786c\u4ef6\u4e4b\u4e0a\uff0c\u662f\u64cd\u4f5c\u7cfb\u7edf\u7684\u8c03\u4f18\u3002\u8fd9\u5305\u62ec\u8c03\u6574\u5185\u6838\u53c2\u6570\uff0c\u5982\u7f51\u7edc\u7f13\u51b2\u533a\u5927\u5c0f\u3001\u6587\u4ef6\u53e5\u67c4\u9650\u5236\u7b49\uff0c\u4e3a\u6570\u636e\u5e93\u8f6f\u4ef6\u7684\u8fd0\u884c\u63d0\u4f9b\u4e00\u4e2a\u66f4\u7406\u60f3\u7684\u5bbf\u4e3b\u73af\u5883\u3002<\/li>\n\n\n\n<li><strong>\u6570\u636e\u5e93\u8f6f\u4ef6\u5c42\u4f18\u5316<\/strong>\uff1a\u8fd9\u4e00\u5c42\u805a\u7126\u4e8e\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\uff08DBMS\uff09\u672c\u8eab\u7684\u914d\u7f6e\u3002\u4ee5MySQL\u4e3a\u4f8b\uff0c\u8fd9\u53ef\u80fd\u6d89\u53ca\u5230\u8c03\u6574\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u3001\u4fee\u6539InnoDB\u5b58\u50a8\u5f15\u64ce\u7684\u7279\u5b9a\u53c2\u6570\uff08\u5982<code>innodb_flush_log_at_trx_commit<\/code>\u6765\u5e73\u8861\u6570\u636e\u5b89\u5168\u6027\u4e0e\u6027\u80fd\uff09\u3002<\/li>\n\n\n\n<li><strong>\u5e94\u7528\u5c42SQL\u4f18\u5316<\/strong>\uff1a\u4f4d\u4e8e\u91d1\u5b57\u5854\u7684\u9876\u7aef\uff0c\u8fd9\u662f\u6211\u4eec\u4f5c\u4e3a\u5e94\u7528\u5f00\u53d1\u8005\u6700\u5e38\u63a5\u89e6\u3001\u4e5f\u6700\u80fd\u53d1\u6325\u4e3b\u89c2\u80fd\u52a8\u6027\u7684\u5c42\u9762\u3002\u5b83\u76f4\u63a5\u9488\u5bf9\u4e1a\u52a1\u903b\u8f91\u4ea7\u751f\u7684SQL\u67e5\u8be2\u8bed\u53e5\u8fdb\u884c\u5206\u6790\u4e0e\u91cd\u6784\u3002<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"488\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-1024x488.png\" alt=\"\" class=\"wp-image-18960\" style=\"width:500px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-1024x488.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-300x143.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-768x366.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-830x395.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-230x110.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-350x167.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244-480x229.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-244.png 1276w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u8fd9\u4e2a\u6a21\u578b\u544a\u8bc9\u6211\u4eec\uff0c\u8d8a\u5e95\u5c42\u7684\u4f18\u5316\uff0c\u5176\u5f71\u54cd\u8303\u56f4\u8d8a\u5e7f\uff0c\u4f46\u901a\u5e38\u4e5f\u9700\u8981\u66f4\u4e13\u4e1a\u7684\u77e5\u8bc6\u548c\u66f4\u9ad8\u7684\u64cd\u4f5c\u6743\u9650\u3002\u800c\u9876\u5c42\u7684SQL\u4f18\u5316\uff0c\u867d\u7136\u9700\u8981\u9488\u5bf9\u5177\u4f53\u4e1a\u52a1\u573a\u666f\uff0c\u4f46\u5176\u7cbe\u786e\u6027\u548c\u5e26\u6765\u7684\u6027\u80fd\u56de\u62a5\u7387\u5f80\u5f80\u662f\u6700\u9ad8\u7684\u3002<\/p>\n\n\n\n<p>\u4ece\u6570\u636e\u5e93\u5185\u90e8\u5de5\u4f5c\u539f\u7406\u7684\u89c6\u89d2\u6765\u770b\uff0c\u6240\u6709SQL\u4f18\u5316\u7684\u52aa\u529b\uff0c\u6700\u7ec8\u90fd\u6307\u5411\u4e24\u4e2a\u6839\u672c\u76ee\u6807\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u6700\u5c0f\u5316\u78c1\u76d8I\/O<\/strong>\uff1a\u78c1\u76d8\u8bbf\u95ee\u662f\u6570\u636e\u5e93\u6700\u6602\u8d35\u7684\u64cd\u4f5c\u4e4b\u4e00\u3002\u4f18\u5316\u7684\u6838\u5fc3\u5728\u4e8e\u5c3d\u53ef\u80fd\u907f\u514d\u5168\u8868\u626b\u63cf\u8fd9\u79cd\u5730\u6bef\u5f0f\u641c\u7d22\uff0c\u786e\u4fdd\u67e5\u8be2\u8bf7\u6c42\u80fd\u591f\u7cbe\u51c6\u5730\u547d\u4e2d\u7d22\u5f15\uff0c\u6700\u7406\u60f3\u7684\u60c5\u51b5\u662f\u5b9e\u73b0\u201c\u8986\u76d6\u7d22\u5f15\u201d\uff0c\u8ba9\u67e5\u8be2\u6240\u9700\u7684\u6570\u636e\u5b8c\u5168\u5728\u7d22\u5f15\u7ed3\u6784\u4e2d\u5f97\u5230\u6ee1\u8db3\uff0c\u65e0\u9700\u56de\u8868\u8bbf\u95ee\u4e3b\u6570\u636e\u3002<\/li>\n\n\n\n<li><strong>\u6700\u5c0f\u5316CPU\u4e0e\u5185\u5b58\u5f00\u9500<\/strong>\uff1a\u6570\u636e\u5e93\u4e0d\u4ec5\u662f\u5b58\u50a8\u7cfb\u7edf\uff0c\u4e5f\u662f\u8ba1\u7b97\u7cfb\u7edf\u3002\u590d\u6742\u7684\u6392\u5e8f\uff08<code>ORDER BY<\/code>\uff09\u3001\u5206\u7ec4\u805a\u5408\uff08<code>GROUP BY<\/code>\uff09\u548c\u53bb\u91cd\uff08<code>DISTINCT<\/code>\uff09\u7b49\u64cd\u4f5c\u4f1a\u5927\u91cf\u6d88\u8017CPU\u548c\u5185\u5b58\u8d44\u6e90\u3002\u4f18\u5316\u7684\u76ee\u6807\u5c31\u662f\u5c06\u8fd9\u4e9b\u8ba1\u7b97\u538b\u529b\u5c3d\u53ef\u80fd\u5730\u6d88\u9664\u6216\u524d\u7f6e\u5904\u7406\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u638c\u63e1\u8fd9\u4e9b\u7406\u8bba\u6846\u67b6\u662f\u57fa\u7840\u3002\u4f46\u5728\u771f\u5b9e\u7684\u9762\u8bd5\u6216\u5de5\u4f5c\u573a\u666f\u4e2d\uff0c\u7a7a\u8c08\u7406\u8bba\u4ef7\u503c\u6709\u9650\uff0c\u771f\u6b63\u7684\u6311\u6218\u5728\u4e8e\u5b9e\u8df5\u3002\u800c\u5b9e\u8df5\u7684\u7b2c\u4e00\u6b65\uff0c\u5c31\u662f\u8981\u5b66\u4f1a\u4f7f\u7528\u8bca\u65ad\u6027\u80fd\u95ee\u9898\u7684\u201c\u542c\u8bca\u5668\u201d\u2014\u2014<code>EXPLAIN<\/code>\u547d\u4ee4\u3002<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-black-color\"><strong>1.1 \u6d1e\u5bdf<code>EXPLAIN<\/code>\u6267\u884c\u8ba1\u5212<\/strong><\/mark><\/p>\n\n\n\n<p>\u53ef\u4ee5\u65ad\u8a00\uff0c\u4efb\u4f55\u4e0d\u719f\u6089<code>EXPLAIN<\/code>\u7684\u540e\u7aef\u5de5\u7a0b\u5e08\uff0c\u5176\u6570\u636e\u5e93\u6280\u80fd\u90fd\u662f\u4e0d\u5b8c\u6574\u7684\u3002<code>EXPLAIN<\/code>\u7684\u7528\u6cd5\u6781\u5176\u7b80\u5355\uff0c\u53ea\u9700\u5728\u4f60\u7684<code>SELECT<\/code>\u8bed\u53e5\u524d\u52a0\u4e0a\u5b83\uff0cMySQL\u5c31\u4f1a\u8fd4\u56de\u4e00\u4efd\u8be6\u7ec6\u7684\u201c\u6267\u884c\u8ba1\u5212\u201d\uff0c\u8fd9\u4efd\u8ba1\u5212\u63ed\u793a\u4e86\u4f18\u5316\u5668\u5c06\u5982\u4f55\u5904\u7406\u4f60\u7684\u67e5\u8be2\u8bf7\u6c42\u3002<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">-- \u793a\u4f8b\uff1a\u5206\u6790\u4e00\u6761\u6392\u5e8f\u5206\u9875\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212<br>EXPLAIN select * from tx_user.user order by uid desc limit 5;<\/pre>\n\n\n\n<p>\u6267\u884c\u8ba1\u5212\u7684\u8f93\u51fa\u7ed3\u679c\u5305\u542b\u4e86\u4e30\u5bcc\u7684\u4fe1\u606f\uff0c\u5bf9\u4e8e\u521d\u5b66\u8005\u53ef\u80fd\u6709\u4e9b\u671b\u800c\u751f\u754f\u3002\u4f46\u5728\u9762\u8bd5\u548c\u65e5\u5e38\u5de5\u4f5c\u4e2d\uff0c\u6211\u4eec\u53ea\u9700\u8981\u91cd\u70b9\u5173\u6ce8\u5e76\u7406\u89e3\u4ee5\u4e0b\u51e0\u4e2a\u5173\u952e\u5217\uff1a<\/p>\n\n\n\n<ol>\n<li><code>type<\/code>\uff1a\u8bbf\u95ee\u7c7b\u578b\u3002\u8fd9\u662f\u8bc4\u4f30\u67e5\u8be2\u6548\u7387\u7684\u6838\u5fc3\u6307\u6807\uff0c\u5b83\u63ed\u793a\u4e86MySQL\u67e5\u627e\u6570\u636e\u6240\u91c7\u7528\u7684\u65b9\u5f0f\u3002\u6027\u80fd\u4ece\u6700\u4f18\u5230\u6700\u5dee\u7684\u987a\u5e8f\u4e3a\uff1a<code>system<\/code> > <code>const<\/code> > <code>eq_ref<\/code> > <code>ref<\/code> > <code>range<\/code> > <code>index<\/code> > <code>ALL<\/code>\u3002\n<ul>\n<li><code>system<\/code>\u3001<code>const<\/code>\uff1a\u5e38\u91cf\u7ea7\u522b\u67e5\u627e\uff0c\u610f\u5473\u7740\u67e5\u8be2\u77ac\u95f4\u5c31\u80fd\u5b9a\u4f4d\u5230\u552f\u4e00\u7684\u4e00\u884c\u8bb0\u5f55\u3002<\/li>\n\n\n\n<li><code>eq_ref<\/code>\u3001<code>ref<\/code>\uff1a\u57fa\u4e8e\u7d22\u5f15\u7684\u7b49\u503c\u67e5\u8be2\uff0c\u6548\u7387\u975e\u5e38\u9ad8\u3002<\/li>\n\n\n\n<li><code>range<\/code>\uff1a\u7d22\u5f15\u8303\u56f4\u626b\u63cf\uff0c\u4f8b\u5982 <code>WHERE id BETWEEN 100 AND 200<\/code>\u3002<\/li>\n\n\n\n<li><code>index<\/code>\uff1a\u7d22\u5f15\u5168\u626b\u63cf\u3002\u5b83\u867d\u7136\u4f7f\u7528\u4e86\u7d22\u5f15\uff0c\u4f46\u9700\u8981\u904d\u5386\u6574\u4e2a\u7d22\u5f15\u6811\uff0c\u5f53\u7d22\u5f15\u672c\u8eab\u5f88\u5927\u65f6\uff0c\u5f00\u9500\u4e5f\u4e0d\u5c0f\u3002<\/li>\n\n\n\n<li><code>ALL<\/code>\uff1a\u5168\u8868\u626b\u63cf\u3002\u8fd9\u662f\u6027\u80fd\u7684\u201c\u7ea2\u706f\u201d\uff0c\u610f\u5473\u7740MySQL\u5c06\u653e\u5f03\u7d22\u5f15\uff0c\u4ece\u5934\u5230\u5c3e\u8bfb\u53d6\u6574\u5f20\u8868\uff0c\u662f\u4f18\u5316\u7684\u9996\u8981\u5bf9\u8c61\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><code>possible_keys<\/code>\uff1a\u5019\u9009\u7d22\u5f15\u3002\u5217\u51fa\u4e86MySQL\u8ba4\u4e3a\u53ef\u80fd\u9002\u7528\u4e8e\u6b64\u67e5\u8be2\u7684\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><code>key<\/code>\uff1a\u5b9e\u9645\u4f7f\u7528\u7684\u7d22\u5f15\u3002\u8fd9\u662f\u4f18\u5316\u5668\u5728\u7efc\u5408\u8bc4\u4f30\u540e\uff0c\u6700\u7ec8\u9009\u62e9\u7684\u7d22\u5f15\u3002\u5982\u679c\u4e3a<code>NULL<\/code>\uff0c\u5219\u8868\u793a\u6ca1\u6709\u4f7f\u7528\u4efb\u4f55\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><code>rows<\/code>\uff1a\u9884\u4f30\u626b\u63cf\u884c\u6570\u3002\u4f18\u5316\u5668\u9884\u6d4b\u4e3a\u4e86\u6ee1\u8db3\u67e5\u8be2\uff0c\u9700\u8981\u68c0\u67e5\u7684\u8bb0\u5f55\u6570\u91cf\u3002\u8fd9\u4e2a\u6570\u5b57\u8d8a\u5c0f\u8d8a\u597d\u3002<\/li>\n\n\n\n<li><code>filtered<\/code>\uff1a\u884c\u8fc7\u6ee4\u767e\u5206\u6bd4\u3002\u8868\u793a\u5728<code>rows<\/code>\u9884\u4f30\u626b\u63cf\u7684\u884c\u4e2d\uff0c\u6709\u591a\u5c11\u767e\u5206\u6bd4\u7684\u8bb0\u5f55\u80fd\u591f\u6ee1\u8db3<code>WHERE<\/code>\u5b50\u53e5\u7684\u6761\u4ef6\u3002\u6b64\u503c\u8d8a\u9ad8\uff0c\u8bf4\u660e\u7d22\u5f15\u7684\u8fc7\u6ee4\u6548\u679c\u8d8a\u7cbe\u51c6\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u6211\u4eec\u4e0d\u5fc5\u5f3a\u884c\u80cc\u8bf5\u6240\u6709\u5b57\u6bb5\u7684\u542b\u4e49\u3002SQL\u4f18\u5316\u7684\u5b9e\u8df5\u8fc7\u7a0b\uff0c\u672c\u5c31\u662f\u4e00\u4e2a\u201c<strong>\u5206\u6790-\u5047\u8bbe-\u9a8c\u8bc1<\/strong>\u201d\u7684\u8fed\u4ee3\u5faa\u73af\u3002\u901a\u8fc7<code>EXPLAIN<\/code>\u5206\u6790\u51fa\u73b0\u72b6\uff0c\u63d0\u51fa\u4f18\u5316\u5047\u8bbe\uff08\u5982\u6539\u5199SQL\u3001\u8c03\u6574\u7d22\u5f15\uff09\uff0c\u5b9e\u65bd\u540e\u518d\u6b21\u7528<code>EXPLAIN<\/code>\u9a8c\u8bc1\u6548\u679c\uff0c\u76f4\u81f3\u6027\u80fd\u8fbe\u6807\u3002<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"468\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-1024x468.png\" alt=\"\" class=\"wp-image-18962\" style=\"width:558px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-1024x468.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-300x137.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-768x351.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-830x380.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-230x105.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-350x160.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245-480x220.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-245.png 1268w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><strong>1.2 \u7d22\u5f15\u8bbe\u8ba1<\/strong><\/p>\n\n\n\n<p>\u65e2\u7136SQL\u4f18\u5316\u7684\u6838\u5fc3\u5728\u4e8e\u7d22\u5f15\uff0c\u90a3\u4e48\u5982\u4f55\u8bbe\u8ba1\u51fa\u9ad8\u6548\u7684\u7d22\u5f15\u5c31\u6210\u4e86\u4e00\u95e8\u827a\u672f\u3002\u8fd9\u5e76\u975e\u6709\u56fa\u5b9a\u7684\u6807\u51c6\u7b54\u6848\uff0c\u800c\u662f\u5728\u7406\u89e3\u4e1a\u52a1\u548c\u6570\u636e\u5206\u5e03\u57fa\u7840\u4e0a\u7684\u6743\u8861\u3002\u4ee5\u4e0b\u662f\u51e0\u6761\u88ab\u5e7f\u6cdb\u8ba4\u53ef\u7684\u6700\u4f73\u5b9e\u8df5\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>\u4e3a\u9ad8\u9891\u8fc7\u6ee4\u6761\u4ef6\u7684\u8c13\u8bcd\u5217\u5efa\u7acb\u7d22\u5f15<\/strong>\uff1a\u8fd9\u662f\u6700\u57fa\u672c\u7684\u539f\u5219\u3002\u90a3\u4e9b\u5728<code>WHERE<\/code>\u5b50\u53e5\u4e2d\u9891\u7e41\u51fa\u73b0\u7684\u3001\u7528\u4e8e\u7b5b\u9009\u6570\u636e\u7684\u5217\uff0c\u662f\u521b\u5efa\u7d22\u5f15\u7684\u9996\u9009\u3002<\/li>\n\n\n\n<li><strong>\u4e3a\u6392\u5e8f\u64cd\u4f5c\u7684\u6392\u5e8f\u5217\u5efa\u7acb\u7d22\u5f15<\/strong>\uff1a<code>ORDER BY<\/code>\u5b50\u53e5\u80cc\u540e\u7684<code>filesort<\/code>\uff08\u6587\u4ef6\u6392\u5e8f\uff09\u662f\u5e38\u89c1\u7684\u6027\u80fd\u74f6\u9888\u3002\u4e3a\u6392\u5e8f\u5217\u5efa\u7acb\u7d22\u5f15\uff0c\u53ef\u4ee5\u5229\u7528\u7d22\u5f15B+\u6811\u7684\u5929\u7136\u6709\u5e8f\u6027\uff0c\u76f4\u63a5\u514d\u53bb\u6392\u5e8f\u6b65\u9aa4\u3002<\/li>\n\n\n\n<li><strong>\u4e3a\u5916\u952e\u53ca\u5173\u8054\u5217\u5efa\u7acb\u7d22\u5f15<\/strong>\uff1a\u5728\u8fdb\u884c\u8868\u8fde\u63a5\uff08<code>JOIN<\/code>\uff09\u65f6\uff0c\u5173\u8054\u5b57\u6bb5\u5fc5\u987b\u6709\u7d22\u5f15\uff0c\u5426\u5219\u4f1a\u5bfc\u81f4\u5d4c\u5957\u5faa\u73af\u8fde\u63a5\u7684\u6027\u80fd\u707e\u96be\u3002<\/li>\n\n\n\n<li><strong>\u4f18\u5148\u9009\u62e9\u9ad8\u57fa\u6570\uff08\u9ad8\u533a\u5206\u5ea6\uff09\u7684\u5217<\/strong>\uff1a\u5217\u4e2d\u552f\u4e00\u503c\u7684\u6570\u91cf\u8d8a\u591a\uff0c\u5176\u201c\u57fa\u6570\u201d\u5c31\u8d8a\u9ad8\uff0c\u7d22\u5f15\u7684\u9009\u62e9\u6027\u5c31\u8d8a\u597d\uff0c\u67e5\u8be2\u65f6\u80fd\u66f4\u5feb\u5730\u5b9a\u4f4d\u6570\u636e\u3002\u5728\u521b\u5efa\u8054\u5408\u7d22\u5f15\u65f6\uff0c\u4e5f\u5e94\u5c06\u57fa\u6570\u6700\u9ad8\u7684\u5217\u653e\u5728\u6700\u5de6\u4fa7\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>1.3 \u5927\u8868DDL\u64cd\u4f5c\u7684\u98ce\u9669\u4e0e\u89c4\u907f<\/strong><\/p>\n\n\n\n<p>\u5728\u4f18\u5316\u8fc7\u7a0b\u4e2d\uff0c\u65b0\u589e\u6216\u4fee\u6539\u7d22\u5f15\u662f\u5e38\u89c4\u64cd\u4f5c\u3002\u7136\u800c\uff0c\u5bf9\u4e00\u5f20\u6570\u636e\u91cf\u5de8\u5927\u7684\u8868\u6267\u884cDDL\uff08\u6570\u636e\u5b9a\u4e49\u8bed\u8a00\uff09\u64cd\u4f5c\uff0c\u9690\u85cf\u7740\u5de8\u5927\u7684\u98ce\u9669\u3002<\/p>\n\n\n\n<p>\u5176\u6838\u5fc3\u75c7\u7ed3\u5728\u4e8e\uff0cDDL\u64cd\u4f5c\uff08\u5982<code>ALTER TABLE<\/code>\uff09\u53ef\u80fd\u4f1a\u8bf7\u6c42\u4e00\u4e2a\u6392\u4ed6\u6027\u7684\u5143\u6570\u636e\u9501\uff08MDL\uff09\uff0c\u8fd9\u4e2a\u9501\u4f1a\u963b\u585e\u8be5\u8868\u4e0a\u7684\u6240\u6709\u540e\u7eed\u8bfb\u5199\u8bf7\u6c42\uff0c\u76f4\u5230DDL\u64cd\u4f5c\u5b8c\u6210\u3002\u5bf9\u4e8e\u4e00\u5f20\u5343\u4e07\u7ea7\u751a\u81f3\u4ebf\u7ea7\u7684\u5927\u8868\uff0c\u52a0\u7d22\u5f15\u53ef\u80fd\u8017\u65f6\u6570\u5206\u949f\u5230\u6570\u5c0f\u65f6\uff0c\u957f\u65f6\u95f4\u7684\u9501\u8868\u5bf9\u7ebf\u4e0a\u4e1a\u52a1\u800c\u8a00\u662f\u4e0d\u53ef\u63a5\u53d7\u7684\u3002<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"313\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-1024x313.png\" alt=\"\" class=\"wp-image-18963\" style=\"width:572px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-1024x313.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-300x92.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-768x235.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-830x254.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-230x70.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-350x107.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246-480x147.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-246.png 1274w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u56e0\u6b64\uff0c\u9488\u5bf9\u5927\u8868\u7684\u7ed3\u6784\u53d8\u66f4\uff0c\u5fc5\u987b\u91c7\u7528\u66f4\u7cbe\u7ec6\u5316\u7684\u65b9\u6848\u6765\u89c4\u907f\u98ce\u9669\u3002\u4e1a\u754c\u4e3b\u6d41\u7684\u65b9\u6848\u6709\u4ee5\u4e0b\u4e09\u79cd\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u8ba1\u5212\u5185\u505c\u673a\u53d8\u66f4<\/strong>\uff1a\u5728\u4e1a\u52a1\u4f4e\u5cf0\u671f\u6216\u7ef4\u62a4\u7a97\u53e3\uff0c\u6682\u505c\u76f8\u5173\u670d\u52a1\uff0c\u7136\u540e\u6267\u884cDDL\u64cd\u4f5c\u3002\u8fd9\u662f\u6700\u7b80\u5355\u76f4\u63a5\u7684\u65b9\u6848\uff0c\u4f46\u5bf9\u7528\u6237\u4f53\u9a8c\u6709\u5f71\u54cd\u3002<\/li>\n\n\n\n<li><strong>\u5229\u7528\u4e1a\u52a1\u4f4e\u8c37\u671f\u53d8\u66f4<\/strong>\uff1a\u5728\u51cc\u6668\u7b49\u6d41\u91cf\u6700\u4f4e\u7684\u65f6\u95f4\u6bb5\u8fdb\u884c\u64cd\u4f5c\u3002\u6b64\u65b9\u6848\u7684\u98ce\u9669\u5728\u4e8e\uff0c\u5982\u679c\u64cd\u4f5c\u8017\u65f6\u8d85\u51fa\u9884\u671f\uff0c\u53ef\u80fd\u4f1a\u5f71\u54cd\u5230\u6b21\u65e5\u767d\u5929\u7684\u4e1a\u52a1\u9ad8\u5cf0\u3002<\/li>\n\n\n\n<li>\u201c\u5f71\u5b50\u8868\u201d\u65b9\u6848\uff08\u5728\u7ebfDDL\uff09\uff1a\u8fd9\u662f\u5728\u4e0d\u4e2d\u65ad\u670d\u52a1\u7684\u524d\u63d0\u4e0b\u5b8c\u6210\u53d8\u66f4\u7684\u6700\u4f73\u5b9e\u8df5\u3002\u5176\u6838\u5fc3\u601d\u60f3\u662f\u201c\u91d1\u8749\u8131\u58f3\u201d\uff1a<\/li>\n\n\n\n<li>a. \u521b\u5efa\u4e00\u5f20\u4e0e\u539f\u8868\u7ed3\u6784\u76f8\u540c\u7684\u65b0\u8868\uff08\u5f71\u5b50\u8868\uff09\uff0c\u5e76\u5728\u8fd9\u5f20\u65b0\u8868\u4e0a\u63d0\u524d\u6267\u884cDDL\uff0c\u4f8b\u5982\u52a0\u4e0a\u65b0\u7d22\u5f15\u3002<\/li>\n\n\n\n<li>b. \u5c06\u539f\u8868\u7684\u5168\u91cf\u6570\u636e\u901a\u8fc7\u5de5\u5177\u62f7\u8d1d\u5230\u5f71\u5b50\u8868\u3002<\/li>\n\n\n\n<li>c. \u5728\u62f7\u8d1d\u8fc7\u7a0b\u4e2d\uff0c\u901a\u8fc7\u67d0\u79cd\u673a\u5236\uff08\u5982\u89e6\u53d1\u5668\u6216\u8ba2\u9605binlog\uff09\u5c06\u539f\u8868\u7684\u589e\u91cf\u6570\u636e\u5b9e\u65f6\u540c\u6b65\u5230\u5f71\u5b50\u8868\u3002<\/li>\n\n\n\n<li>d. \u5f85\u6570\u636e\u5b8c\u5168\u540c\u6b65\u540e\uff0c\u5728\u4e00\u4e2a\u539f\u5b50\u6027\u7684\u64cd\u4f5c\u4e2d\uff0c\u5c06\u539f\u8868\u91cd\u547d\u540d\u4e3a\u5907\u4efd\u8868\uff0c\u5c06\u5f71\u5b50\u8868\u91cd\u547d\u540d\u4e3a\u539f\u8868\uff0c\u5b8c\u6210\u7ebf\u4e0a\u6d41\u91cf\u7684\u5207\u6362\u3002<\/li>\n<\/ol>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"716\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-1024x716.png\" alt=\"\" class=\"wp-image-18964\" style=\"width:480px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-1024x716.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-300x210.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-768x537.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-830x580.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-230x161.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-350x245.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247-480x336.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-247.png 1264w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>2. \u9762\u8bd5\u573a\u666f\u4e0b\u7684\u5e94\u5bf9\u7b56\u7565<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u8981\u5728\u9762\u8bd5\u4e2d\u5145\u5206\u5c55\u73b0\u4f60\u7684SQL\u4f18\u5316\u80fd\u529b\uff0c\u4f60\u9700\u8981\u51c6\u5907\u51e0\u4e2a\u6709\u6df1\u5ea6\u3001\u6709\u7ec6\u8282\u7684\u5b9e\u6218\u6848\u4f8b\u3002\u8fd9\u4e9b\u6848\u4f8b\u5e94\u80fd\u53cd\u6620\u51fa\u4f60\u5bf9\u6570\u636e\u5e93\u5e95\u5c42\u539f\u7406\u7684\u7406\u89e3\u3002\u4f60\u53ef\u4ee5\u4ece\u4ee5\u4e0b\u51e0\u65b9\u9762\u7740\u624b\u51c6\u5907\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>\u76d8\u70b9\u9879\u76ee\u7ecf\u9a8c<\/strong>\uff1a\u68b3\u7406\u4f60\u8d1f\u8d23\u8fc7\u7684\u6838\u5fc3\u4e1a\u52a1\u8868\u7ed3\u6784\uff0c\u5206\u6790\u5176\u7d22\u5f15\u8bbe\u8ba1\u662f\u5426\u5408\u7406\u3002\u627e\u51fa\u6267\u884c\u6700\u9891\u7e41\u7684\u51e0\u6761SQL\uff0c\u7528<code>EXPLAIN<\/code>\u5ba1\u89c6\u5b83\u4eec\u662f\u5426\u90fd\u8fd0\u884c\u5728\u6700\u4f73\u72b6\u6001\u3002<\/li>\n\n\n\n<li><strong>\u590d\u76d8\u771f\u5b9e\u6848\u4f8b<\/strong>\uff1a\u56de\u987e\u56e2\u961f\u5185\u90e8\u5904\u7406\u8fc7\u7684\u6162SQL\u95ee\u9898\u3002\u5173\u952e\u662f\u8981\u5f04\u6e05\u695a\u95ee\u9898\u7684\u53d1\u73b0\u3001\u5206\u6790\u3001\u89e3\u51b3\u548c\u9a8c\u8bc1\u7684\u5168\u8fc7\u7a0b\uff0c\u5e76\u7528\u4f18\u5316\u524d\u540e\u7684\u6027\u80fd\u6570\u636e\uff08\u5982\u54cd\u5e94\u65f6\u95f4\u3001CPU\u4f7f\u7528\u7387\uff09\u6765\u91cf\u5316\u4f60\u7684\u6210\u679c\u3002<\/li>\n\n\n\n<li><strong>\u9884\u6f14\u6df1\u5ea6\u8ffd\u95ee<\/strong>\uff1a\u5bf9\u4f60\u51c6\u5907\u7684\u6bcf\u4e2a\u6848\u4f8b\uff0c\u90fd\u8981\u6362\u4f4d\u601d\u8003\uff0c\u6a21\u62df\u9762\u8bd5\u5b98\u53ef\u80fd\u63d0\u51fa\u7684\u6df1\u5165\u95ee\u9898\u3002\u4f8b\u5982\uff0c\u201c\u4e3a\u4ec0\u4e48\u4f18\u5316\u5668\u6ca1\u6709\u9009\u62e9\u4f60\u8ba4\u4e3a\u6700\u4f18\u7684\u7d22\u5f15\uff1f\u201d\uff0c\u201c\u4f60\u8fd9\u4e2a\u65b9\u6848\u5728\u5e76\u53d1\u573a\u666f\u4e0b\u6709\u6ca1\u6709\u6570\u636e\u4e00\u81f4\u6027\u7684\u95ee\u9898\uff1f\u201d<\/li>\n<\/ul>\n\n\n\n<p>\u603b\u7684\u6765\u8bf4\uff0cSQL\u4f18\u5316\u7684\u77e5\u8bc6\u70b9\u7e41\u591a\u4e14\u7410\u788e\uff0c\u4f46\u9762\u8bd5\u4e2d\u4f60\u65e0\u9700\u9762\u9762\u4ff1\u5230\u3002\u5173\u952e\u662f\u638c\u63e1\u4e3b\u52a8\u6743\uff0c\u901a\u8fc7\u4f60\u7cbe\u5fc3\u51c6\u5907\u7684\u6848\u4f8b\uff0c\u5c06\u9762\u8bd5\u5b98\u7684\u63d0\u95ee\u5f15\u5bfc\u5230\u4f60\u6700\u64c5\u957f\u7684\u9886\u57df\u3002<\/p>\n\n\n\n<p>\u5f53\u9762\u8bd5\u5b98\u629b\u51fa\u201c\u4f60\u505a\u8fc7\u54ea\u4e9b\u6027\u80fd\u4f18\u5316\uff1f\u201d\u6216\u201c\u5982\u4f55\u964d\u4f4e\u63a5\u53e3\u54cd\u5e94\u65f6\u95f4\uff1f\u201d\u8fd9\u7c7b\u5f00\u653e\u6027\u95ee\u9898\u65f6\uff0c\u4f60\u5b8c\u5168\u53ef\u4ee5\u4e3b\u52a8\u5c06\u8bdd\u9898\u5f15\u5411SQL\u4f18\u5316\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\u201c\u5728\u6211\u4e4b\u524d\u8d1f\u8d23\u7684XX\u6838\u5fc3\u7cfb\u7edf\u4e2d\uff0c\u6027\u80fd\u662f\u4e00\u4e2a\u5173\u952e\u7684\u975e\u529f\u80fd\u6027\u6307\u6807\uff0c\u6211\u4eec\u8981\u6c42\u6838\u5fc3\u63a5\u53e3\u7684P99\u54cd\u5e94\u65f6\u95f4\u5728100ms\u4ee5\u5185\u3002\u4e3a\u4e86\u8fbe\u6210\u8fd9\u4e00\u76ee\u6807\uff0c\u6211\u4e3b\u5bfc\u4e86\u4e00\u7cfb\u5217\u4f18\u5316\u5de5\u4f5c\uff0c\u5176\u4e2dSQL\u5c42\u9762\u7684\u8c03\u4f18\u662f\u89c1\u6548\u6700\u5feb\u3001\u6536\u6548\u6700\u5927\u7684\u4e00\u73af\u3002\u201d<\/pre>\n\n\n\n<p>\u5982\u679c\u9762\u8bd5\u5b98\u8ffd\u95ee\u5177\u4f53\u5982\u4f55\u505a\uff0c\u4f60\u53ef\u4ee5\u8fd9\u6837\u5c55\u5f00\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\u201c\u6211\u4eec\u7684\u6392\u67e5\u6d41\u7a0b\u901a\u5e38\u59cb\u4e8e\u6162\u67e5\u8be2\u76d1\u63a7\u7cfb\u7edf\u3002\u4e00\u65e6\u53d1\u73b0\u63a5\u53e3\u8d85\u65f6\u544a\u8b66\uff0c\u6211\u4eec\u4f1a\u5b9a\u4f4d\u5230\u5177\u4f53\u7684\u6162SQL\u3002\u63a5\u7740\uff0c\u6838\u5fc3\u7684\u8bca\u65ad\u5de5\u5177\u5c31\u662fEXPLAIN\uff0c\u901a\u8fc7\u5b83\u6765\u5206\u6790\u6267\u884c\u8ba1\u5212\uff0c\u5224\u65ad\u662f\u5426\u5b58\u5728\u5168\u8868\u626b\u63cf\u3001\u7d22\u5f15\u9009\u62e9\u662f\u5426\u5408\u7406\u3001\u6709\u65e0\u4e0d\u5fc5\u8981\u7684filesort\u7b49\u95ee\u9898\u3002\u5b9a\u4f4d\u6839\u56e0\u540e\uff0c\u6211\u4eec\u4f1a\u63d0\u51fa\u4f18\u5316\u5047\u8bbe\uff0c\u53ef\u80fd\u662f\u6539\u5199SQL\uff0c\u4e5f\u53ef\u80fd\u662f\u8c03\u6574\u6216\u65b0\u589e\u7d22\u5f15\u3002\u65b9\u6848\u5b9e\u65bd\u540e\uff0c\u6211\u4eec\u4f1a\u518d\u6b21\u901a\u8fc7EXPLAIN\u548c\u538b\u529b\u6d4b\u8bd5\u6765\u9a8c\u8bc1\u4f18\u5316\u6548\u679c\uff0c\u5f62\u6210\u4e00\u4e2a\u5b8c\u6574\u7684PDCA\u95ed\u73af\u3002\u201d<\/pre>\n\n\n\n<p>\u6b64\u65f6\uff0c\u4fbf\u662f\u5f15\u51fa\u4f60\u51c6\u5907\u7684\u5b9e\u6218\u6848\u4f8b\u7684\u6700\u4f73\u65f6\u673a\u3002\u4ee5\u4e0b\u662f\u6211\u6574\u7406\u7684\u4e00\u4e9b\u5728\u751f\u4ea7\u73af\u5883\u4e2d\u975e\u5e38\u5178\u578b\u7684\u4f18\u5316\u6848\u4f8b\uff0c\u5efa\u8bae\u4f60\u4eb2\u624b\u5b9e\u8df5\uff0c\u52a0\u6df1\u7406\u89e3\u3002<\/p>\n\n\n\n<p><strong>2.1 \u5229\u7528\u8986\u76d6\u7d22\u5f15\u6d88\u9664\u56de\u8868<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u4e00\u4e2a\u9ad8\u9891\u67e5\u8be2\u6700\u521d\u4e3a\u4e86\u65b9\u4fbf\u5199\u6210\u4e86<code>SELECT *<\/code>\uff0c\u4f46\u4e1a\u52a1\u903b\u8f91\u5b9e\u9645\u53ea\u5173\u5fc3A\u3001B\u3001C\u4e09\u5217\u3002<code>WHERE<\/code>\u6761\u4ef6\u4e5f\u4e3b\u8981\u56f4\u7ed5\u8fd9\u4e09\u5217\u3002\u901a\u8fc7<code>EXPLAIN<\/code>\u53d1\u73b0\uff0c\u5373\u4f7f\u67e5\u8be2\u8d70\u4e86\u7d22\u5f15\uff0c\u4e5f\u5b58\u5728\u5927\u91cf\u7684\u56de\u8868\u64cd\u4f5c\u3002<\/p>\n\n\n\n<p>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5\uff1a\u56de\u8868\uff08Table Access by Index Rowid\uff09\u662f\u6307\u5728\u901a\u8fc7\u4e8c\u7ea7\u7d22\u5f15\u627e\u5230\u4e3b\u952eID\u540e\uff0c\u8fd8\u9700\u518d\u6b21\u6839\u636e\u4e3b\u952eID\u53bb\u805a\u7c07\u7d22\u5f15\u4e2d\u67e5\u627e\u6574\u884c\u6570\u636e\u7684\u8fc7\u7a0b\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u589e\u52a0\u4e86\u989d\u5916\u7684I\/O\u5f00\u9500\u3002<\/p>\n\n\n\n<p>\u6211\u7684\u89e3\u51b3\u65b9\u6848\u662f\uff0c\u521b\u5efa\u4e00\u4e2a\u5305\u542b\u4e86\u67e5\u8be2\u6240\u9700\u5168\u90e8\u5217\uff08A\u3001B\u3001C\uff09\u7684\u8054\u5408\u7d22\u5f15\u3002\u7136\u540e\uff0c\u5c06SQL\u8bed\u53e5\u4eceSELECT *\u7cbe\u7b80\u4e3aSELECT A, B, C\u3002<\/p>\n\n\n\n<p>\u8fd9\u6837\uff0c\u67e5\u8be2\u6240\u9700\u7684\u6240\u6709\u6570\u636e\u90fd\u53ef\u4ee5\u76f4\u63a5\u4ece\u8fd9\u4e2a\u8054\u5408\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u4e2d\u83b7\u53d6\uff0cMySQL\u65e0\u9700\u518d\u56de\u5230\u4e3b\u952e\u7d22\u5f15\u53bb\u62c9\u53d6\u6570\u636e\uff0c\u8fd9\u4fbf\u662f\u201c\u8986\u76d6\u7d22\u5f15\u201d\u3002\u4f18\u5316\u540e\uff0c\u67e5\u8be2\u8017\u65f6\u4ece\u767e\u6beb\u79d2\u7ea7\u522b\u9aa4\u964d\u81f31\u6beb\u79d2\u4ee5\u5185\u3002<\/p>\n\n\n\n<p><strong>\u6838\u5fc3\u6d1e\u5bdf<\/strong>\uff1a\u5bf9\u4e8e\u8bfb\u5bc6\u96c6\u578b\u7684\u9ad8\u9891\u67e5\u8be2\uff0c\u8bbe\u8ba1\u6070\u5f53\u7684\u8986\u76d6\u7d22\u5f15\u662f\u6027\u4ef7\u6bd4\u6700\u9ad8\u7684\u4f18\u5316\u624b\u6bb5\u4e4b\u4e00\u3002<\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>2.2 \u501f\u52a9\u7d22\u5f15\u6709\u5e8f\u6027\u4f18\u5316\u6392\u5e8f<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u4e00\u4e2a\u67e5\u8be2\u7528\u6237\u64cd\u4f5c\u5386\u53f2\u7684\u63a5\u53e3\uff0cSQL\u4e3a<code>SELECT ... FROM ... WHERE uid = ? ORDER BY create_time DESC<\/code>\u3002\u968f\u7740\u5355\u4e2a\u7528\u6237\u6570\u636e\u91cf\u7684\u589e\u957f\uff0c\u67e5\u8be2\u56e0<code>filesort<\/code>\uff08\u6587\u4ef6\u6392\u5e8f\uff09\u800c\u53d8\u5f97\u7f13\u6162\u3002<\/p>\n\n\n\n<p>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5\uff1afilesort\u662f\u6570\u636e\u5e93\u5728\u65e0\u6cd5\u5229\u7528\u7d22\u5f15\u987a\u5e8f\u65f6\uff0c\u5728\u5185\u5b58\u6216\u78c1\u76d8\u4e2d\u8fdb\u884c\u7684\u989d\u5916\u6392\u5e8f\u64cd\u4f5c\uff0c\u6210\u672c\u9ad8\u6602\u3002\u6211\u7684\u89e3\u51b3\u65b9\u6848\u662f\uff0c\u521b\u5efa\u4e00\u4e2a(uid, create_time)\u7684\u8054\u5408\u7d22\u5f15\u3002<\/p>\n\n\n\n<p>\u6839\u636eB+\u6811\u7d22\u5f15\u7684\u7ed3\u6784\u7279\u6027\uff0c\u5f53uid\u76f8\u540c\u65f6\uff0c\u7d22\u5f15\u9879\u672c\u8eab\u5c31\u662f\u6309\u7167create_time\u6709\u5e8f\u6392\u5217\u7684\u3002\u56e0\u6b64\uff0c\u5f53WHERE\u5b50\u53e5\u786e\u5b9a\u4e86uid\u540e\uff0c\u6570\u636e\u5e93\u53ef\u4ee5\u76f4\u63a5\u6309\u7d22\u5f15\u987a\u5e8f\u8bfb\u53d6\u6570\u636e\uff0c\u4ece\u800c\u5b8c\u5168\u907f\u514d\u4e86\u6392\u5e8f\u6b65\u9aa4\u3002\u8fd9\u4e2a\u6539\u52a8\u5c06\u67e5\u8be2\u8017\u65f6\u4ece\u79d2\u7ea7\u4f18\u5316\u5230\u4e86\u51e0\u5341\u6beb\u79d2\u3002<\/p>\n\n\n\n<p><strong>\u6838\u5fc3\u6d1e\u5bdf<\/strong>\uff1a\u4efb\u4f55<code>ORDER BY<\/code>\u3001<code>GROUP BY<\/code>\u6216<code>DISTINCT<\/code>\u64cd\u4f5c\uff0c\u90fd\u5e94\u9996\u5148\u601d\u8003\u80fd\u5426\u901a\u8fc7\u8c03\u6574\u7d22\u5f15\u6765\u5229\u7528\u5176\u5929\u7136\u7684\u6709\u5e8f\u6027\uff0c\u8fd9\u662f\u6d88\u9664\u6570\u636e\u5e93\u6392\u5e8f\u5f00\u9500\u7684\u6839\u672c\u65b9\u6cd5\u3002<\/p>\n\n\n\n<p><strong>2.3 <code>COUNT(*)<\/code>\u7684\u4f18\u5316\u8def\u5f84<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u5728InnoDB\u5b58\u50a8\u5f15\u64ce\u4e2d\uff0c<code>SELECT COUNT(*)<\/code>\u4f1a\u89e6\u53d1\u5168\u8868\u626b\u63cf\uff0c\u56e0\u4e3aInnoDB\u4e3a\u4e86\u652f\u6301MVCC\uff0c\u6ca1\u6709\u50cfMyISAM\u90a3\u6837\u7ef4\u62a4\u4e00\u4e2a\u5b9e\u65f6\u7684\u603b\u884c\u6570\u3002<\/p>\n\n\n\n<p><strong>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5<\/strong>\uff1a\u9488\u5bf9\u6b64\u95ee\u9898\uff0c\u9700\u8981\u6839\u636e\u4e1a\u52a1\u5bf9\u7cbe\u786e\u6027\u7684\u8981\u6c42\u6765\u9009\u62e9\u65b9\u6848\u3002<\/p>\n\n\n\n<ol>\n<li><strong>\u8fd1\u4f3c\u503c\u65b9\u6848<\/strong>\uff1a\u5982\u679c\u4e1a\u52a1\u80fd\u5bb9\u5fcd\u4e00\u4e2a\u4f30\u7b97\u503c\uff08\u4f8b\u5982\uff0c\u663e\u793a\u201c\u7ea6\u6709N\u6761\u201d\uff09\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7<code>EXPLAIN<\/code>\u4e00\u6761\u4e0d\u5e26<code>COUNT<\/code>\u7684\u67e5\u8be2\uff0c\u76f4\u63a5\u53d6\u5176\u8fd4\u56de\u7684<code>rows<\/code>\u5b57\u6bb5\u4f5c\u4e3a\u8fd1\u4f3c\u7ed3\u679c\u3002<\/li>\n\n\n\n<li><strong>\u7cbe\u786e\u503c\u65b9\u6848\uff08\u5916\u90e8\u8ba1\u6570\uff09<\/strong>\uff1a\u5982\u679c\u5fc5\u987b\u662f\u7cbe\u786e\u503c\uff0c\u66f4\u4f18\u7684\u67b6\u6784\u65b9\u6848\u662f\u5728\u5916\u90e8\u7cfb\u7edf\uff08\u5982Redis\uff09\u4e2d\u7ef4\u62a4\u4e00\u4e2a\u8ba1\u6570\u5668\u3002\u5f53\u4e1a\u52a1\u4ee3\u7801\u6267\u884c<code>INSERT<\/code>\u6216<code>DELETE<\/code>\u64cd\u4f5c\u65f6\uff0c\u540c\u6b65\u53bb\u66f4\u65b0\u8fd9\u4e2a\u8ba1\u6570\u5668\u3002<\/li>\n<\/ol>\n\n\n\n<p><strong>\u5ef6\u4f38\u63a2\u8ba8<\/strong>\uff1a\u91c7\u7528\u5916\u90e8\u8ba1\u6570\u65b9\u6848\uff0c\u5fc5\u987b\u8003\u8651\u6570\u636e\u4e00\u81f4\u6027\u95ee\u9898\u3002\u5982\u679c\u5728\u66f4\u65b0\u6570\u636e\u5e93\u540e\uff0c\u66f4\u65b0Redis\u5931\u8d25\u4e86\u600e\u4e48\u529e\uff1f\u8fd9\u5f15\u5165\u4e86\u5206\u5e03\u5f0f\u4e8b\u52a1\u7684\u590d\u6742\u6027\u3002\u4e00\u4e2a\u66f4\u4f18\u96c5\u7684\u89e3\u8026\u65b9\u6848\u662f\uff0c\u5e94\u7528\u5c42\u53ea\u7ba1\u64cd\u4f5c\u6570\u636e\u5e93\uff0c\u7136\u540e\u901a\u8fc7\u8ba2\u9605\u6570\u636e\u5e93\u7684binlog\u65e5\u5fd7\uff08\u4f8b\u5982\u4f7f\u7528Canal\u7ec4\u4ef6\uff09\uff0c\u7531\u4e00\u4e2a\u72ec\u7acb\u7684\u540c\u6b65\u670d\u52a1\u6765\u5f02\u6b65\u5730\u3001\u53ef\u9760\u5730\u66f4\u65b0Redis\u4e2d\u7684\u8ba1\u6570\u503c\uff0c\u4fdd\u8bc1\u6700\u7ec8\u4e00\u81f4\u6027\u3002<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"298\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-1024x298.png\" alt=\"\" class=\"wp-image-18965\" style=\"width:626px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-1024x298.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-300x87.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-768x224.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-830x242.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-230x67.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-350x102.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248-480x140.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-248.png 1304w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><strong>2.4 \u5ba1\u614e\u4f7f\u7528\u7d22\u5f15\u63d0\u793a<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u5728\u6781\u5c11\u6570\u60c5\u51b5\u4e0b\uff0cMySQL\u7684\u67e5\u8be2\u4f18\u5316\u5668\u53ef\u80fd\u4f1a\u56e0\u4e3a\u7edf\u8ba1\u4fe1\u606f\u4e0d\u51c6\u7b49\u539f\u56e0\uff0c\u505a\u51fa\u9519\u8bef\u7684\u5224\u65ad\uff0c\u9009\u62e9\u4e86\u4e00\u4e2a\u6027\u80fd\u8f83\u5dee\u7684\u6267\u884c\u8ba1\u5212\u3002<\/p>\n\n\n\n<p><strong>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5<\/strong>\uff1a\u5f53\u901a\u8fc7<code>EXPLAIN<\/code>\u786e\u8ba4\u4f18\u5316\u5668\u9009\u9519\u4e86\u7d22\u5f15\uff0c\u4e14\u901a\u8fc7\u5176\u4ed6\u65b9\u5f0f\uff08\u5982\u6539\u5199SQL\uff09\u65e0\u6cd5\u7ea0\u6b63\u65f6\uff0c\u53ef\u4ee5\u8003\u8651\u4f7f\u7528\u7d22\u5f15\u63d0\u793a\uff08\u5982<code>FORCE INDEX<\/code>\uff09\u6765\u5f3a\u5236\u4f18\u5316\u5668\u4f7f\u7528\u6211\u4eec\u6307\u5b9a\u7684\u7d22\u5f15\u3002\u6211\u66fe\u5728\u4e00\u4e2a\u6848\u4f8b\u4e2d\uff0c\u901a\u8fc7<code>FORCE INDEX<\/code>\u5f3a\u5236\u67e5\u8be2\u8d70\u4e86\u6b63\u786e\u7684\u7d22\u5f15\uff0c\u6027\u80fd\u83b7\u5f97\u4e86\u6570\u91cf\u7ea7\u7684\u63d0\u5347\u3002<\/p>\n\n\n\n<p><strong>\u6838\u5fc3\u6d1e\u5bdf<\/strong>\uff1a\u7d22\u5f15\u63d0\u793a\u662f\u8d4b\u4e88\u5f00\u53d1\u8005\u7684\u201c\u6700\u7ec8\u624b\u6bb5\u201d\uff0c\u5b83\u76f8\u5f53\u4e8e\u7ed5\u8fc7\u4e86\u4f18\u5316\u5668\u7684\u81ea\u4e3b\u51b3\u7b56\u3002\u8fd9\u4f1a\u964d\u4f4e\u4ee3\u7801\u7684\u53ef\u7ef4\u62a4\u6027\uff0c\u56e0\u4e3a\u5f53\u6570\u636e\u5206\u5e03\u6216\u8868\u7ed3\u6784\u53d8\u5316\u540e\uff0c\u66fe\u7ecf\u6700\u4f18\u7684\u7d22\u5f15\u53ef\u80fd\u4e0d\u518d\u662f\u6700\u4f73\u9009\u62e9\u3002\u56e0\u6b64\uff0c\u975e\u5230\u4e07\u4e0d\u5f97\u5df2\uff0c\u4e0d\u5e94\u4f7f\u7528\u3002<\/p>\n\n\n\n<p><strong>2.5 <code>WHERE<\/code>\u4e0e<code>HAVING<\/code>\u7684\u6b63\u786e\u5206\u5de5<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u5728\u7ef4\u62a4\u4e00\u4e2a\u9057\u7559\u7cfb\u7edf\u65f6\uff0c\u53d1\u73b0\u6709SQL\u5c06\u4e00\u4e2a\u666e\u901a\u7684\u5b57\u6bb5\u7b49\u503c\u8fc7\u6ee4\u6761\u4ef6\u5199\u5728\u4e86<code>HAVING<\/code>\u5b50\u53e5\u4e2d\uff0c\u800c\u975e<code>WHERE<\/code>\u5b50\u53e5\u3002<\/p>\n\n\n\n<p><strong>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5<\/strong>\uff1a\u5fc5\u987b\u6e05\u6670\u5730\u7406\u89e3SQL\u7684\u903b\u8f91\u6267\u884c\u987a\u5e8f\uff1a<code>FROM<\/code> -&gt; <code>WHERE<\/code> -&gt; <code>GROUP BY<\/code> -&gt; <code>HAVING<\/code> -&gt; <code>SELECT<\/code> -&gt; <code>ORDER BY<\/code>\u3002<code>WHERE<\/code>\u5b50\u53e5\u5728\u5206\u7ec4\u805a\u5408\u524d\u5bf9\u539f\u59cb\u6570\u636e\u884c\u8fdb\u884c\u8fc7\u6ee4\uff0c\u800c<code>HAVING<\/code>\u5728\u5206\u7ec4\u805a\u5408\u540e\u5bf9\u7ed3\u679c\u96c6\u8fdb\u884c\u8fc7\u6ee4\u3002\u5c06\u8fc7\u6ee4\u6761\u4ef6\u5c3d\u53ef\u80fd\u5730\u524d\u7f6e\u5230<code>WHERE<\/code>\u9636\u6bb5\uff0c\u53ef\u4ee5\u6781\u5927\u5730\u51cf\u5c11\u53c2\u4e0e\u540e\u7eed\u805a\u5408\u8ba1\u7b97\u7684\u6570\u636e\u91cf\u3002\u6211\u5c06\u90a3\u4e2a\u6761\u4ef6\u4ece<code>HAVING<\/code>\u8fc1\u79fb\u5230<code>WHERE<\/code>\u540e\uff0c\u67e5\u8be2\u6027\u80fd\u63d0\u5347\u4e8640%\u3002<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"580\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-1024x580.png\" alt=\"\" class=\"wp-image-18966\" style=\"width:536px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-1024x580.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-300x170.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-768x435.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-830x470.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-230x130.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-350x198.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249-480x272.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-249.png 1300w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><strong>\u6838\u5fc3\u6d1e\u5bdf<\/strong>\uff1a<code>HAVING<\/code>\u7684\u4e13\u5c5e\u804c\u8d23\u662f\u7528\u4e8e\u5bf9\u805a\u5408\u51fd\u6570\uff08\u5982<code>SUM() > 100<\/code>\uff09\u7684\u7ed3\u679c\u8fdb\u884c\u8fc7\u6ee4\u3002\u6240\u6709\u9488\u5bf9\u539f\u59cb\u8868\u5b57\u6bb5\u7684\u8fc7\u6ee4\uff0c\u90fd\u5e94\u65e0\u4e00\u4f8b\u5916\u5730\u653e\u5728<code>WHERE<\/code>\u5b50\u53e5\u4e2d\u3002<\/p>\n\n\n\n<p><strong>2.6 \u7834\u89e3\u6df1\u5ea6\u5206\u9875\u7684\u6027\u80fd\u9677\u9631<\/strong><\/p>\n\n\n\n<p><strong>\u95ee\u9898\u80cc\u666f<\/strong>\uff1a\u91c7\u7528<code>LIMIT offset, count<\/code>\u8fdb\u884c\u5206\u9875\u67e5\u8be2\u65f6\uff0c\u5f53<code>offset<\/code>\u503c\u975e\u5e38\u5927\u65f6\uff08\u5373\u6df1\u5ea6\u5206\u9875\uff09\uff0c\u6027\u80fd\u4f1a\u6025\u5267\u6076\u5316\u3002\u56e0\u4e3a\u6570\u636e\u5e93\u9700\u8981\u5148\u626b\u63cf<code>offset + count<\/code>\u884c\u6570\u636e\uff0c\u7136\u540e\u629b\u5f03\u524d\u9762\u7684<code>offset<\/code>\u884c\uff0c\u8fd9\u4e2a\u8fc7\u7a0b\u7684\u6210\u672c\u4e0e<code>offset<\/code>\u6210\u6b63\u6bd4\u3002<\/p>\n\n\n\n<p>\u4f18\u5316\u601d\u8def\u4e0e\u5b9e\u8df5\uff1a\u4f18\u5316\u7684\u6838\u5fc3\u601d\u60f3\u662f\u907f\u514d\u5927\u504f\u79fb\u91cf\u626b\u63cf\uff0c\u8f6c\u800c\u4f7f\u7528\u201c\u6e38\u6807\u201d\u6216\u201c\u952e\u96c6\u5206\u9875\u201d\uff08Keyset Pagination\uff09\u7684\u65b9\u5f0f\u3002\u6211\u7684\u5b9e\u8df5\u662f\uff0c\u5728\u67e5\u8be2\u6761\u4ef6\u4e2d\uff0c\u5229\u7528\u4e0a\u4e00\u9875\u7ed3\u679c\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u7684ID\uff08\u6216\u4e00\u4e2a\u6709\u5e8f\u4e14\u552f\u4e00\u7684\u952e\uff09\u6765\u8fdb\u884c\u5b9a\u4f4d\u3002\u4f8b\u5982\uff0c\u67e5\u8be2\u4e0b\u4e00\u9875\u7684SQL\u53d8\u4e3a WHERE id &gt; [last_page_max_id] ORDER BY id ASC LIMIT [page_size]\u3002<\/p>\n\n\n\n<p>\u8fd9\u6837\uff0c\u65e0\u8bba\u7ffb\u5230\u7b2c\u51e0\u9875\uff0cLIMIT\u7684\u504f\u79fb\u91cf\u59cb\u7ec8\u4e3a0\uff0c\u67e5\u8be2\u6027\u80fd\u53ef\u4ee5\u4fdd\u6301\u7a33\u5b9a\u5728\u6beb\u79d2\u7ea7\u3002<\/p>\n\n\n\n<p><strong>\u6838\u5fc3\u6d1e\u5bdf<\/strong>\uff1a\u6df1\u5ea6\u5206\u9875\u7684\u6027\u80fd\u95ee\u9898\u5728\u6570\u636e\u91cf\u5c0f\u7684\u6d4b\u8bd5\u73af\u5883\u4e2d\u6781\u6613\u88ab\u5ffd\u7565\u3002\u5728\u8bbe\u8ba1\u4efb\u4f55\u5206\u9875\u63a5\u53e3\u65f6\uff0c\u90fd\u5e94\u9ed8\u8ba4\u91c7\u7528\u57fa\u4e8e\u6e38\u6807\u7684\u67e5\u8be2\u65b9\u5f0f\uff0c\u4ece\u6839\u6e90\u4e0a\u675c\u7edd\u6b64\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>3. \u6838\u5fc3\u8981\u70b9\u56de\u987e<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u4eca\u5929\u6211\u4eec\u7cfb\u7edf\u6027\u5730\u63a2\u8ba8\u4e86SQL\u4f18\u5316\u7684\u4e09\u4e2a\u5173\u952e\u524d\u7f6e\u77e5\u8bc6\uff1a<code>EXPLAIN<\/code>\u5de5\u5177\u3001\u7d22\u5f15\u5217\u9009\u62e9\u548c\u5728\u7ebfDDL\u65b9\u6848\uff0c\u5e76\u7ed3\u5408\u516d\u4e2a\u8d34\u8fd1\u751f\u4ea7\u7684\u6848\u4f8b\u8fdb\u884c\u4e86\u6df1\u5165\u5256\u6790\u3002<\/p>\n\n\n\n<p>\u6700\u540e\u9700\u8981\u5f3a\u8c03\u4e00\u70b9\uff1a\u6280\u672f\u7684\u6d77\u6d0b\u6d69\u701a\u65e0\u57a0\uff0c\u4f60\u4e0d\u53ef\u80fd\u638c\u63e1\u6240\u6709\u7ec6\u679d\u672b\u8282\u3002\u5728\u9762\u8bd5\u4e2d\uff0c\u5173\u952e\u662f\u638c\u63e1\u5bf9\u8bdd\u7684\u4e3b\u5bfc\u6743\u3002\u901a\u8fc7\u4f60\u7cbe\u5fc3\u51c6\u5907\u7684\u3001\u6709\u6df1\u5ea6\u3001\u6709\u7ec6\u8282\u7684\u6848\u4f8b\uff0c\u5c06\u9762\u8bd5\u5b98\u7684\u601d\u8def\u5f15\u5bfc\u5230\u4f60\u6700\u719f\u6089\u7684\u9886\u57df\u3002\u8fd9\u6837\uff0c\u5373\u4fbf\u8868\u9762\u4e0a\u662f\u4ed6\u5728\u63d0\u95ee\uff0c\u5b9e\u9645\u4e0a\u6574\u4e2a\u4ea4\u6d41\u7684\u8282\u594f\u5df2\u5728\u4f60\u7684\u638c\u63a7\u4e4b\u4e2d\u3002<\/p>\n\n\n\n<p>\u53cd\u4e4b\uff0c\u5982\u679c\u65e0\u6cd5\u4e3b\u5bfc\u8282\u594f\uff0c\u88ab\u52a8\u5730\u63a5\u53d7\u9762\u8bd5\u5b98\u5929\u9a6c\u884c\u7a7a\u7684\u63d0\u95ee\uff0c\u90a3\u4e48\u89e6\u53ca\u5230\u4f60\u7684\u77e5\u8bc6\u76f2\u533a\u4e5f\u5c31\u5728\u6240\u96be\u514d\u4e86\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"_3-\u6838\u5fc3\u8981\u70b9\u56de\u987e\"><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/sql_optimization.html#_3-\u6838\u5fc3\u8981\u70b9\u56de\u987e\"><\/a><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"_2-6-\u7834\u89e3\u6df1\u5ea6\u5206\u9875\u7684\u6027\u80fd\u9677\u9631\"><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/sql_optimization.html#_2-6-\u7834\u89e3\u6df1\u5ea6\u5206\u9875\u7684\u6027\u80fd\u9677\u9631\"><\/a><\/h3>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"_2-5-where\u4e0ehaving\u7684\u6b63\u786e\u5206\u5de5\"><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/sql_optimization.html#_2-5-where\u4e0ehaving\u7684\u6b63\u786e\u5206\u5de5\"><\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"<p>\u8f6c\u8f7d\uff1a\u5728\u505aSQL\u6027\u80fd\u8c03\u4f18\u7684\u65f6\u5019\u5982\u4f55\u7cbe\u51c6\u5b9a\u4f4d\u5e76\u89e3\u51b3\u95ee\u9898 \u4eca\u5929\u60f3\u548c\u5927\u5bb6\u6df1\u5165\u804a\u804a\u6570\u636e\u5e93\u6027\u80fd\u4f18\u5316\u4e2d\u4e00\u4e2a\u7ed5\u4e0d\u5f00\u7684\u8bdd\u9898\u2014\u2014 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"_links":{"self":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/18959"}],"collection":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=18959"}],"version-history":[{"count":3,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/18959\/revisions"}],"predecessor-version":[{"id":18968,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/18959\/revisions\/18968"}],"wp:attachment":[{"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=18959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=18959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=18959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}