{"id":1704,"date":"2023-08-25T17:16:39","date_gmt":"2023-08-25T09:16:39","guid":{"rendered":"https:\/\/zhang.mba\/?p=1704"},"modified":"2023-08-25T17:24:59","modified_gmt":"2023-08-25T09:24:59","slug":"mysql-you-hua","status":"publish","type":"post","link":"https:\/\/zhang.mba\/index.php\/2023\/08\/25\/17\/16\/39\/1704\/mysql-you-hua\/database\/zhangzhiqi\/","title":{"rendered":"MySQL\u4f18\u5316"},"content":{"rendered":"<h2><a id=\"1%E4%B8%BA%E4%BB%80%E4%B9%88%E8%A6%81%E8%BF%9B%E8%A1%8C%E6%95%B0%E6%8D%AE%E5%BA%93%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#1%E4%B8%BA%E4%BB%80%E4%B9%88%E8%A6%81%E8%BF%9B%E8%A1%8C%E6%95%B0%E6%8D%AE%E5%BA%93%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>1. \u4e3a\u4ec0\u4e48\u8981\u8fdb\u884c\u6570\u636e\u5e93\u4f18\u5316<\/h2>\n<ol>\n<li>\u907f\u514d\u7f51\u7ad9\u9875\u9762\u51fa\u73b0\u8bbf\u95ee\u9519\u8bef\n<ul>\n<li>\u7531\u4e8e\u6570\u636e\u5e93\u8fde\u63a5timeout\u4ea7\u751f\u9875\u97625xx\u9519\u8bef , to many connection<\/li>\n<li>\u7531\u4e8e\u6162\u67e5\u8be2\u9020\u6210\u9875\u9762\u65e0\u6cd5\u52a0\u8f7d : \u7531\u4e8e\u6570\u636e\u5e93\u65e0\u6cd5\u53ca\u65f6\u7684\u8fd4\u56de\u6570\u636e, \u5bfc\u81f4\u9875\u9762\u4e00\u76f4\u65e0\u6cd5\u8fd4\u56de<\/li>\n<li>\u7531\u4e8e\u963b\u585e\u9020\u6210\u6570\u636e\u65e0\u6cd5\u63d0\u4ea4 :<\/li>\n<\/ul>\n<\/li>\n<li>\u589e\u52a0\u6570\u636e\u5e93\u7684\u7a33\u5b9a\u6027\n<ul>\n<li>\u5f88\u591a\u6570\u636e\u5e93\u95ee\u9898\u90fd\u662f\u7531\u4e8e\u4f4e\u6548\u7684\u67e5\u8be2\u5f15\u8d77\u7684<\/li>\n<\/ul>\n<\/li>\n<li>\u4f18\u5316\u7528\u6237\u4f53\u9a8c\n<ul>\n<li>\u6d41\u7545\u9875\u9762\u7684\u8bbf\u95ee\u901f\u5ea6<\/li>\n<li>\u826f\u597d\u7684\u7f51\u7ad9\u529f\u80fd\u4f53\u9a8c<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h2><a id=\"2-mysql%E6%95%B0%E6%8D%AE%E5%BA%93%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#2-mysql%E6%95%B0%E6%8D%AE%E5%BA%93%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>2. MySql\u6570\u636e\u5e93\u4f18\u5316<\/h2>\n<p>\u53ef\u4ee5\u4ece\u54ea\u51e0\u4e2a\u65b9\u9762\u8fdb\u884c\u6570\u636e\u5e93\u7684\u4f18\u5316\uff1f\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081451970.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081451970.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ol>\n<li>\n<p>SQL\u53ca\u7d22\u5f15\u4f18\u5316<\/p>\n<p>\u6839\u636e\u9700\u6c42\u5199\u51fa\u826f\u597d\u7684SQL\uff0c\u5e76\u521b\u5efa\u6709\u6548\u7684\u7d22\u5f15\uff0c\u5b9e\u73b0\u67d0\u4e00\u79cd\u9700\u6c42\u53ef\u4ee5\u591a\u79cd\u5199\u6cd5\uff0c\u8fd9\u65f6\u5019\u6211\u4eec\u5c31\u8981\u9009\u62e9\u4e00\u79cd\u6548\u7387\u6700\u9ad8\u7684\u5199\u6cd5\u3002\u8fd9\u4e2a\u65f6\u5019\u5c31\u8981\u4e86\u89e3sql\u4f18\u5316<\/p>\n<\/li>\n<li>\n<p>\u6570\u636e\u5e93\u8868\u7ed3\u6784\u4f18\u5316<\/p>\n<p>\u6839\u636e\u6570\u636e\u5e93\u7684\u8303\u5f0f\uff0c\u8bbe\u8ba1\u8868\u7ed3\u6784\uff0c\u8868\u7ed3\u6784\u8bbe\u8ba1\u7684\u597d\u76f4\u63a5\u5173\u7cfb\u5230\u5199SQL\u8bed\u53e5\u3002<\/p>\n<\/li>\n<li>\n<p>\u7cfb\u7edf\u914d\u7f6e\u4f18\u5316<\/p>\n<p>\u5927\u591a\u6570\u8fd0\u884c\u5728Linux\u673a\u5668\u4e0a\uff0c\u5982tcp\u8fde\u63a5\u6570\u7684\u9650\u5236\u3001\u6253\u5f00\u6587\u4ef6\u6570\u7684\u9650\u5236\u3001\u5b89\u5168\u6027\u7684\u9650\u5236\uff0c\u56e0\u6b64\u6211\u4eec\u8981\u5bf9\u8fd9\u4e9b\u914d\u7f6e\u8fdb\u884c\u76f8\u5e94\u7684\u4f18\u5316\u3002<\/p>\n<\/li>\n<li>\n<p>\u786c\u4ef6\u914d\u7f6e\u4f18\u5316<\/p>\n<p>\u9009\u62e9\u9002\u5408\u6570\u636e\u5e93\u670d\u52a1\u7684cpu\uff0c\u66f4\u5feb\u7684IO\uff0c\u66f4\u9ad8\u7684\u5185\u5b58\uff1bcpu\u5e76\u4e0d\u662f\u8d8a\u591a\u8d8a\u597d\uff0c\u67d0\u4e9b\u6570\u636e\u5e93\u7248\u672c\u6709\u6700\u5927\u7684\u9650\u5236\uff0c\uff29\uff2f\u64cd\u4f5c\u5e76\u4e0d\u662f\u51cf\u5c11\u963b\u585e\u3002<\/p>\n<\/li>\n<\/ol>\n<blockquote>\n<p>\u6ce8\uff1a\u901a\u8fc7\u4e0a\u56fe\u53ef\u4ee5\u770b\u51fa\uff0c\u8be5\u91d1\u5b57\u5854\u4e2d\uff0c\u4f18\u5316\u7684\u6210\u672c\u4ece\u4e0b\u800c\u4e0a\u9010\u6e10\u589e\u9ad8\uff0c\u800c\u4f18\u5316\u7684\u6548\u679c\u4f1a\u9010\u6e10\u964d\u4f4e\u3002<\/p>\n<\/blockquote>\n<h2><a id=\"3-sql%E5%8F%8A%E7%B4%A2%E5%BC%95%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#3-sql%E5%8F%8A%E7%B4%A2%E5%BC%95%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>3. SQL\u53ca\u7d22\u5f15\u4f18\u5316<\/h2>\n<h3><a id=\"3-1%E5%87%86%E5%A4%87%E6%95%B0%E6%8D%AE\" class=\"anchor\" aria-hidden=\"true\" href=\"#3-1%E5%87%86%E5%A4%87%E6%95%B0%E6%8D%AE\"><span class=\"octicon octicon-link\"><\/span><\/a>3.1 \u51c6\u5907\u6570\u636e<\/h3>\n<blockquote>\n<p>\u5728mysql\u5b98\u7f51\u4e2d, \u7ed9\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u4e2a\u5b9e\u4f8b\u6570\u636e\u5e93, \u76f4\u63a5\u5c06\u8fd9\u4e2a\u5b9e\u4f8b\u6570\u636e\u5e93\u5bfc\u5165\u5373\u53ef<\/p>\n<\/blockquote>\n<ol>\n<li>\u9875\u9762\u5730\u5740:\u00a0<strong><a href=\"https:\/\/dev.mysql.com\/doc\/sakila\/en\/sakila-installation.html\">https:\/\/dev.mysql.com\/doc\/sakila\/en\/sakila-installation.html<\/a><\/strong><\/li>\n<\/ol>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081452247.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081452247.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ol start=\"2\">\n<li>\u70b9\u51fb\u5b9e\u4f8b\u6570\u636e\u4e0b\u8f7d\u5730\u5740, \u4e0b\u8f7d\u5373\u53ef<\/li>\n<\/ol>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081452460.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081452460.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ol start=\"3\">\n<li>\u5173\u4e8esakila-db.zip\u538b\u7f29\u5305\u6240\u5305\u542b\u7684\u6587\u4ef6\u5982\u4e0b\u89e3\u91ca<\/li>\n<\/ol>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081453521.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081453521.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>sakila-schema.sql\u6587\u4ef6\u5305\u542b\u521b\u5efaSakila\u6570\u636e\u5e93\u7ed3\u6784\u6240\u9700\u7684\u6240\u6709CREATE\u8bed\u53e5\uff0c\u5305\u62ec\u8868\u3001\u89c6\u56fe\u3001\u5b58\u50a8\u8fc7\u7a0b\u548c\u89e6\u53d1\u5668\u3002\nsakila-data.sql\u6587\u4ef6\u5305\u542b\u586b\u5145sakila-schema\u521b\u5efa\u7684\u7ed3\u6784\u6240\u9700\u7684INSERT\u8bed\u53e5\u3002\u4ee5\u53ca\u5fc5\u987b\u5728\u521d\u59cb\u6570\u636e\u52a0\u8f7d\u4e4b\u540e\u521b\u5efa\u7684\u89e6\u53d1\u5668\u7684\u5b9a\u4e49\u3002\nsakila.mwb\u6587\u4ef6\u662f\u4e00\u4e2aMySQL\u5de5\u4f5c\u53f0\u6570\u636e\u6a21\u578b\uff0c\u60a8\u53ef\u4ee5\u5728MySQL Workbench\u4e2d\u6253\u5f00\u5b83\u6765\u68c0\u67e5\u6570\u636e\u5e93\u7ed3\u6784\u3002\n<\/code><\/pre>\n<ol start=\"4\">\n<li>\u5c06 sakila-db.zip \u4e0a\u4f20\u5230linux, \u5e76\u89e3\u538b<\/li>\n<\/ol>\n<p>\u4f7f\u7528rz\u547d\u4ee4\u4e0a\u4f20\u5373\u53ef: \u5982\u679c\u4f7f\u7528rz\u663e\u793a\u6ca1\u6709\u6b64\u547d\u4ee4, \u8f93\u5165\u00a0<code>yum -y install lrzsz<\/code>\u00a0\u4e0b\u8f7d\u5373\u53ef<\/p>\n<p>\u7531\u4e8e\u662f\u4e00\u4e2azip\u6587\u4ef6, \u9700\u8981\u4e0b\u8f7d unzip \u624d\u80fd\u89e3\u538b\u538b\u7f29\u5305:\u00a0<code>yum -y install unzip<\/code><\/p>\n<p>\u89e3\u538b\u538b\u7f29\u5305: unzip sakila-db.zip<\/p>\n<ol start=\"5\">\n<li>\u5728\u6570\u636e\u5e93\u4e2d\u521b\u5efa\u5bf9\u5e94\u8868\u548c\u5e93<\/li>\n<\/ol>\n<pre><code>\u8fde\u63a5\u6570\u636e\u5e93: shell&gt; mysql -u root -p123456\n\u5bfc\u5165\u6570\u636e:  mysql&gt; SOURCE \/root\/sakila-db\/sakila-schema.sql;\n<\/code><\/pre>\n<ol start=\"6\">\n<li>\u5bfc\u5165\u6570\u636e<\/li>\n<\/ol>\n<pre><code>mysql&gt; SOURCE \/root\/sakila-db\/sakila-data.sql;\n<\/code><\/pre>\n<ol start=\"7\">\n<li>\u9a8c\u8bc1\u662f\u5426\u6210\u529f<\/li>\n<\/ol>\n<pre><code>USE sakila;  # \u4f7f\u7528\u6570\u636e\u5e93\nSHOW TABLES; # \u67e5\u770b\u6240\u6709\u8868\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081453217.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081453217.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>SELECT COUNT(*) FROM film;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081510128.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081510128.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>SELECT COUNT(*) FROM film_text;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081510233.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081510233.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h3><a id=\"3-2%E6%9F%A5%E7%9C%8B%E8%A1%A8%E7%BB%93%E6%9E%84\" class=\"anchor\" aria-hidden=\"true\" href=\"#3-2%E6%9F%A5%E7%9C%8B%E8%A1%A8%E7%BB%93%E6%9E%84\"><span class=\"octicon octicon-link\"><\/span><\/a>3.2 \u67e5\u770b\u8868\u7ed3\u6784<\/h3>\n<blockquote>\n<p>\u53ef\u901a\u8fc7sqlyog\u67e5\u770b\u57fa\u672c\u7ed3\u6784\u5173\u7cfb<\/p>\n<\/blockquote>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081453004.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081453004.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h3><a id=\"3-3%E5%A6%82%E4%BD%95%E5%8F%91%E7%8E%B0%E6%9C%89%E9%97%AE%E9%A2%98%E7%9A%84-sql\" class=\"anchor\" aria-hidden=\"true\" href=\"#3-3%E5%A6%82%E4%BD%95%E5%8F%91%E7%8E%B0%E6%9C%89%E9%97%AE%E9%A2%98%E7%9A%84-sql\"><span class=\"octicon octicon-link\"><\/span><\/a>3.3 \u5982\u4f55\u53d1\u73b0\u6709\u95ee\u9898\u7684SQL<\/h3>\n<blockquote>\n<p>mysql\u63d0\u4f9b\u4e86\u6162\u67e5\u8be2\u65e5\u5fd7\u67e5\u770b\u529f\u80fd, \u53ef\u4ee5\u5e2e\u52a9\u67e5\u8be2\u67d0\u4e00\u6761SQL\u6267\u884c\u7684\u4e00\u4e9b\u72b6\u6001<\/p>\n<\/blockquote>\n<ol>\n<li>\u67e5\u8be2mysql\u662f\u5426\u5f00\u542f\u6162\u67e5\u8be2\u65e5\u5fd7<\/li>\n<\/ol>\n<pre><code>show variables like 'slow_query_log';\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081454636.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081454636.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ol start=\"2\">\n<li>\u5f00\u542fmysql\u7684\u6162\u67e5\u8be2\u65e5\u5fd7:<\/li>\n<\/ol>\n<pre><code>show variables like 'slow_query_log'  ;\n\/\/\u67e5\u770b\u662f\u5426\u5f00\u542f\u6162\u67e5\u8be2\u65e5\u5fd7\n\nset global log_queries_not_using_indexes=on; \/\/ \u5c06\u4e0d\u4f7f\u7528\u7d22\u5f15\u7684\u6162\u67e5\u8be2\u65e5\u5fd7\u8fdb\u884c\u8bb0\u5f55\nset global slow_query_log=on;  \/\/\u5f00\u542f\u6162\u67e5\u8be2\u65e5\u5fd7\n\nshow variables like 'slow_query_log_file';\n\/\/\u67e5\u770b\u6162\u67e5\u8be2\u65e5\u5fd7\u5b58\u50a8\u7684\u4f4d\u7f6e\n\nset global long_query_time=1;  \n\/\/\u5927\u4e8e1\u79d2\u949f\u7684\u6570\u636e\u8bb0\u5f55\u5230\u6162\u65e5\u5fd7\u4e2d\uff0c\u5982\u679c\u8bbe\u7f6e\u4e3a\u9ed8\u8ba40\uff0c\u5219\u4f1a\u6709\u5927\u91cf\u7684\u4fe1\u606f\u5b58\u50a8\u5728\u78c1\u76d8\u4e2d\uff0c\u78c1\u76d8\u5f88\u5bb9\u6613\u6ee1\u6389\n<\/code><\/pre>\n<ol start=\"3\">\n<li>\u68c0\u6d4b\u662f\u5426\u5df2\u7ecf\u5f00\u542f:<\/li>\n<\/ol>\n<pre><code>Show databases;\nUse sakila;\nselect * from store;  \/\/ \u6267\u884c\u67e5\u8be2\nselect * from staff;  \/\/ \u6267\u884c\u67e5\u8be2\n<\/code><\/pre>\n<p>\u76d1\u542c\u65e5\u5fd7\u6587\u4ef6\uff0c\u770b\u662f\u5426\u5199\u5165 : \u6ce8\u610f \u540e\u9762\u7684\u65e5\u5fd7\u6587\u4ef6\u7684\u8def\u5f84\u9700\u8981\u901a\u8fc7\u67e5\u8be2<code>slow_query_log_file<\/code>\u53c2\u6570<\/p>\n<pre><code>tail -100f \/var\/lib\/mysql\/node01-slow.log\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081454879.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081454879.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<hr \/>\n<p>mysql\u6162\u67e5\u8be2\u65e5\u5fd7\u5b58\u50a8\u7684\u683c\u5f0f\u8bf4\u660e:<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081455845.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081455845.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>\u8bf4\u660e\uff1a\n\t1\u3001# Time: 190412 22:05:02    &gt;&gt;&gt;      \u67e5\u8be2\u7684\u6267\u884c\u65f6\u95f4\n\t2\u3001# User@Host: root[root] @ localhost []  Id:     2 &gt;&gt;&gt; \u6267\u884csql\u7684\u4e3b\u673a\u4fe1\u606f\n\t3\u3001# Query_time: 0.001274  Lock_time: 0.000164 Rows_sent: 7  Rows_examined: 7   &gt;&gt;&gt;&gt; SQL\u7684\u6267\u884c\u4fe1\u606f\uff1a\n\t\t\tQuery_time\uff1aSQL\u7684\u67e5\u8be2\u65f6\u95f4\n\t\t\tLock_time\uff1a\u9501\u5b9a\u65f6\u95f4\n\t\t\tRows_sent\uff1a\u6240\u53d1\u9001\u7684\u884c\u6570\n\t\t\tRows_examined\uff1a\u6240\u626b\u63cf\u7684\u884c\u6570\n\t4\u3001SET timestamp=1555077861; &gt;&gt;&gt;&gt; SQL\u6267\u884c\u65f6\u95f4\n\t5\u3001select * from shop;  &gt;&gt;&gt;&gt;&gt; SQL\u7684\u6267\u884c\u5185\u5bb9\n<\/code><\/pre>\n<hr \/>\n<p>\u5982\u4f55\u901a\u8fc7\u6162\u67e5\u65e5\u5fd7\u53d1\u73b0\u6709\u95ee\u9898\u7684SQL<\/p>\n<ol>\n<li>\u67e5\u8be2\u6b21\u6570\u591a\u4e14\u6bcf\u6b21\u67e5\u8be2\u5360\u7528\u65f6\u95f4\u957f\u7684sql\n<ul>\n<li>\u901a\u5e38\u4e3apt-query-digest\u5206\u6790\u7684\u524d\u51e0\u4e2a\u67e5\u8be2\uff1b\u8be5\u5de5\u5177\u53ef\u4ee5\u5f88\u6e05\u695a\u7684\u770b\u51fa\u6bcf\u4e2aSQL\u6267\u884c\u7684\u6b21\u6570\u53ca\u767e\u5206\u6bd4\u7b49\u4fe1\u606f\uff0c\u6267\u884c\u7684\u6b21\u6570\u591a\uff0c\u5360\u6bd4\u6bd4\u8f83\u5927\u7684SQL<\/li>\n<\/ul>\n<\/li>\n<li>IO\u5927\u7684sql\n<ul>\n<li>\u6ce8\u610fpt-query-digest\u5206\u6790\u4e2d\u7684Rows examine\u9879\u3002\u626b\u63cf\u7684\u884c\u6570\u8d8a\u591a\uff0cIO\u8d8a\u5927\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u672a\u547d\u4e2d\u7684\u7d22\u5f15\u7684SQL\n<ul>\n<li>\u6ce8\u610fpt-query-digest\u5206\u6790\u4e2d\u7684Rows examine \u548cRows Send\u7684\u5bf9\u6bd4\u3002\u8bf4\u660e\u8be5SQL\u7684\u7d22\u5f15\u547d\u4e2d\u7387\u4e0d\u9ad8\uff0c\u5bf9\u4e8e\u8fd9\u79cdSQL\uff0c\u6211\u4eec\u8981\u91cd\u70b9\u8fdb\u884c\u5173\u6ce8\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<h2><a id=\"4-mysql%E6%85%A2%E6%9F%A5%E6%97%A5%E5%BF%97%E5%88%86%E6%9E%90%E5%B7%A5%E5%85%B7\" class=\"anchor\" aria-hidden=\"true\" href=\"#4-mysql%E6%85%A2%E6%9F%A5%E6%97%A5%E5%BF%97%E5%88%86%E6%9E%90%E5%B7%A5%E5%85%B7\"><span class=\"octicon octicon-link\"><\/span><\/a>4. MySQL\u6162\u67e5\u65e5\u5fd7\u5206\u6790\u5de5\u5177<\/h2>\n<h3><a id=\"4-1-mysqldumpslow\" class=\"anchor\" aria-hidden=\"true\" href=\"#4-1-mysqldumpslow\"><span class=\"octicon octicon-link\"><\/span><\/a>4.1 mysqldumpslow<\/h3>\n<p>\u5982\u4f55\u8fdb\u884c\u67e5\u770b\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u5982\u679c\u5f00\u542f\u4e86\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u5c31\u4f1a\u751f\u6210\u5f88\u591a\u7684\u6570\u636e\uff0c\u7136\u540e\u6211\u4eec\u5c31\u53ef\u4ee5\u901a\u8fc7\u5bf9\u65e5\u5fd7\u7684\u5206\u6790\uff0c\u751f\u6210\u5206\u6790\u62a5\u8868\uff0c\u7136\u540e\u901a\u8fc7\u62a5\u8868\u8fdb\u884c\u4f18\u5316\u3002<\/p>\n<ul>\n<li>\u5982\u4f55\u4f7f\u7528\u6b64\u5de5\u5177:\n<ul>\n<li>\u53ef\u901a\u8fc7\u547d\u4ee4 : mysqldumpslow -h \u67e5\u770b\u4f7f\u7528\u6559\u7a0b<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081455086.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081455086.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>mysqldumpslow -v  : \u67e5\u770bverbose(\u8be6\u7ec6\u914d\u7f6e)\u4fe1\u606f\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081456840.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081456840.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>mysqldumpslow -t 10 \/var\/lib\/mysql\/mysql-slow.log : \u67e5\u770b\u6162\u67e5\u8be2\u65e5\u5fd7\u7684\u524d10\u4e2a\u5206\u6790\u7ed3\u679c\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081456548.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081456548.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<blockquote>\n<p>\u4e0a\u56fe\u4e24\u6761\u5c31\u662f\u5206\u6790\u7684\u7ed3\u679c\uff0c\u6bcf\u6761\u7ed3\u679c\u90fd\u663e\u793a\u662f\u6267\u884c\u65f6\u95f4\uff0c\u9501\u5b9a\u65f6\u95f4\uff0c\u53d1\u9001\u7684\u884c\u6570\uff0c\u626b\u63cf\u7684\u884c\u6570<\/p>\n<p>\u8fd9\u4e2a\u5de5\u5177\u662f\u6700\u5e38\u7528\u7684\u5de5\u5177\uff0c\u901a\u8fc7\u5b89\u88c5mysql\u8fdb\u884c\u9644\u5e26\u5b89\u88c5\uff0c\u4f46\u662f\u8be5\u5de5\u5177\u7edf\u8ba1\u7684\u7ed3\u679c\u6bd4\u8f83\u5c11\uff0c\u5bf9\u6211\u4eec\u7684\u4f18\u5316\u9501\u8868\u73b0\u7684\u6570\u636e\u8fd8\u662f\u6bd4\u8f83\u5c11. (\u53ef\u4ee5\u770b\u4e0b\u8fd9\u4e2a: pt-query-digest)<\/p>\n<\/blockquote>\n<h2><a id=\"5%E9%80%9A%E8%BF%87-explain%E6%9F%A5%E8%AF%A2%E5%88%86%E6%9E%90sql%E7%9A%84%E6%89%A7%E8%A1%8C%E8%AE%A1%E5%88%92\" class=\"anchor\" aria-hidden=\"true\" href=\"#5%E9%80%9A%E8%BF%87-explain%E6%9F%A5%E8%AF%A2%E5%88%86%E6%9E%90sql%E7%9A%84%E6%89%A7%E8%A1%8C%E8%AE%A1%E5%88%92\"><span class=\"octicon octicon-link\"><\/span><\/a>5. \u901a\u8fc7explain\u67e5\u8be2\u5206\u6790SQL\u7684\u6267\u884c\u8ba1\u5212<\/h2>\n<p>explain : SQL\u7684\u6267\u884c\u8ba1\u5212\u4fa7\u9762\u53cd\u6620\u51fa\u4e86SQL\u7684\u6267\u884c\u6548\u7387\uff0c\u5177\u4f53\u6267\u884c\u65b9\u5f0f\u53ea\u9700\u8981\u5728\u6267\u884c\u7684SQL\u524d\u9762\u52a0\u4e0aexplain\u5173\u952e\u8bcd\u5373\u53ef\u3002<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081456067.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081456067.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ul>\n<li>\u5404\u4e2a\u5b57\u6bb5\u8bf4\u660e<\/li>\n<\/ul>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081456475.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081456475.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081456113.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081456113.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<ol>\n<li>\n<p>id\u5217\u6570\u5b57\u8d8a\u5927\u8d8a\u5148\u6267\u884c\uff0c\u5982\u679c\u8bf4\u6570\u5b57\u4e00\u6837\u5927\uff0c\u90a3\u4e48\u5c31\u4ece\u4e0a\u5f80\u4e0b\u4f9d\u6b21\u6267\u884c\uff0cid\u5217\u4e3anull\u7684\u5c31\u8868\u662f\u8fd9\u662f\u4e00\u4e2a\u7ed3\u679c\u96c6\uff0c\u4e0d\u9700\u8981\u4f7f\u7528\u5b83\u6765\u8fdb\u884c\u67e5\u8be2\u3002<\/p>\n<\/li>\n<li>\n<p>select_type\u5217\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n<p>A\uff1asimple\uff1a\u8868\u793a\u4e0d\u9700\u8981union\u64cd\u4f5c\u6216\u8005\u4e0d\u5305\u542b\u5b50\u67e5\u8be2\u7684\u7b80\u5355select\u67e5\u8be2\u3002\u6709\u8fde\u63a5\u67e5\u8be2\u65f6\uff0c\u5916\u5c42\u7684\u67e5\u8be2\u4e3asimple\uff0c\u4e14\u53ea\u6709\u4e00\u4e2a<\/p>\n<p>B\uff1aprimary\uff1a\u4e00\u4e2a\u9700\u8981union\u64cd\u4f5c\u6216\u8005\u542b\u6709\u5b50\u67e5\u8be2\u7684select\uff0c\u4f4d\u4e8e\u6700\u5916\u5c42\u7684\u5355\u4f4d\u67e5\u8be2\u7684select_type\u5373\u4e3aprimary\u3002\u4e14\u53ea\u6709\u4e00\u4e2a<\/p>\n<p>C\uff1aunion\uff1aunion\u8fde\u63a5\u7684\u4e24\u4e2aselect\u67e5\u8be2\uff0c\u7b2c\u4e00\u4e2a\u67e5\u8be2\u662fdervied\u6d3e\u751f\u8868\uff0c\u9664\u4e86\u7b2c\u4e00\u4e2a\u8868\u5916\uff0c\u7b2c\u4e8c\u4e2a\u4ee5\u540e\u7684\u8868select_type\u90fd\u662funion<\/p>\n<p>D\uff1adependent union\uff1a\u4e0eunion\u4e00\u6837\uff0c\u51fa\u73b0\u5728union \u6216union all\u8bed\u53e5\u4e2d\uff0c\u4f46\u662f\u8fd9\u4e2a\u67e5\u8be2\u8981\u53d7\u5230\u5916\u90e8\u67e5\u8be2\u7684\u5f71\u54cd<\/p>\n<p>E\uff1aunion result\uff1a\u5305\u542bunion\u7684\u7ed3\u679c\u96c6\uff0c\u5728union\u548cunion all\u8bed\u53e5\u4e2d,\u56e0\u4e3a\u5b83\u4e0d\u9700\u8981\u53c2\u4e0e\u67e5\u8be2\uff0c\u6240\u4ee5id\u5b57\u6bb5\u4e3anull<\/p>\n<p>F\uff1asubquery\uff1a\u9664\u4e86from\u5b50\u53e5\u4e2d\u5305\u542b\u7684\u5b50\u67e5\u8be2\u5916\uff0c\u5176\u4ed6\u5730\u65b9\u51fa\u73b0\u7684\u5b50\u67e5\u8be2\u90fd\u53ef\u80fd\u662fsubquery<\/p>\n<p>G\uff1adependent subquery\uff1a\u4e0edependent union\u7c7b\u4f3c\uff0c\u8868\u793a\u8fd9\u4e2asubquery\u7684\u67e5\u8be2\u8981\u53d7\u5230\u5916\u90e8\u8868\u67e5\u8be2\u7684\u5f71\u54cd<\/p>\n<p>H\uff1aderived\uff1afrom\u5b57\u53e5\u4e2d\u51fa\u73b0\u7684\u5b50\u67e5\u8be2\uff0c\u4e5f\u53eb\u505a\u6d3e\u751f\u8868\uff0c\u5176\u4ed6\u6570\u636e\u5e93\u4e2d\u53ef\u80fd\u53eb\u505a\u5185\u8054\u89c6\u56fe\u6216\u5d4c\u5957select<\/p>\n<\/li>\n<li>\n<p>table<\/p>\n<p>\u663e\u793a\u7684\u67e5\u8be2\u8868\u540d\uff0c\u5982\u679c\u67e5\u8be2\u4f7f\u7528\u4e86\u522b\u540d\uff0c\u90a3\u4e48\u8fd9\u91cc\u663e\u793a\u7684\u662f\u522b\u540d\uff0c\u5982\u679c\u4e0d\u6d89\u53ca\u5bf9\u6570\u636e\u8868\u7684\u64cd\u4f5c\uff0c\u90a3\u4e48\u8fd9\u663e\u793a\u4e3anull\uff0c\u5982\u679c\u663e\u793a\u4e3a\u5c16\u62ec\u53f7\u62ec\u8d77\u6765\u7684\u5c31\u8868\u793a\u8fd9\u4e2a\u662f\u4e34\u65f6\u8868\uff0c\u540e\u8fb9\u7684N\u5c31\u662f\u6267\u884c\u8ba1\u5212\u4e2d\u7684id\uff0c\u8868\u793a\u7ed3\u679c\u6765\u81ea\u4e8e\u8fd9\u4e2a\u67e5\u8be2\u4ea7\u751f\u3002\u5982\u679c\u662f\u5c16\u62ec\u53f7\u62ec\u8d77\u6765\u7684&lt;union M,N&gt;\uff0c\u4e0e\u7c7b\u4f3c\uff0c\u4e5f\u662f\u4e00\u4e2a\u4e34\u65f6\u8868\uff0c\u8868\u793a\u8fd9\u4e2a\u7ed3\u679c\u6765\u81ea\u4e8eunion\u67e5\u8be2\u7684id\u4e3aM,N\u7684\u7ed3\u679c\u96c6\u3002<\/p>\n<\/li>\n<li>\n<p>type<\/p>\n<p>\u4f9d\u6b21\u4ece\u597d\u5230\u5dee\uff1asystem\uff0cconst\uff0ceq_ref\uff0cref\uff0cfulltext\uff0cref_or_null\uff0cunique_subquery\uff0cindex_subquery\uff0crange\uff0cindex_merge\uff0cindex\uff0cALL\uff0c\u9664\u4e86all\u4e4b\u5916\uff0c\u5176\u4ed6\u7684type\u90fd\u53ef\u4ee5\u4f7f\u7528\u5230\u7d22\u5f15\uff0c\u9664\u4e86index_merge\u4e4b\u5916\uff0c\u5176\u4ed6\u7684type\u53ea\u53ef\u4ee5\u7528\u5230\u4e00\u4e2a\u7d22\u5f15<\/p>\n<p>A\uff1asystem\uff1a\u8868\u4e2d\u53ea\u6709\u4e00\u884c\u6570\u636e\u6216\u8005\u662f\u7a7a\u8868\uff0c\u4e14\u53ea\u80fd\u7528\u4e8emyisam\u548cmemory\u8868\u3002\u5982\u679c\u662fInnodb\u5f15\u64ce\u8868\uff0ctype\u5217\u5728\u8fd9\u4e2a\u60c5\u51b5\u901a\u5e38\u90fd\u662fall\u6216\u8005index<\/p>\n<p>B\uff1aconst\uff1a\u4f7f\u7528\u552f\u4e00\u7d22\u5f15\u6216\u8005\u4e3b\u952e\uff0c\u8fd4\u56de\u8bb0\u5f55\u4e00\u5b9a\u662f1\u884c\u8bb0\u5f55\u7684\u7b49\u503cwhere\u6761\u4ef6\u65f6\uff0c\u901a\u5e38type\u662fconst\u3002\u5176\u4ed6\u6570\u636e\u5e93\u4e5f\u53eb\u505a\u552f\u4e00\u7d22\u5f15\u626b\u63cf<\/p>\n<p>C\uff1aeq_ref\uff1a\u51fa\u73b0\u5728\u8981\u8fde\u63a5\u8fc7\u4e2a\u8868\u7684\u67e5\u8be2\u8ba1\u5212\u4e2d\uff0c\u9a71\u52a8\u8868\u53ea\u8fd4\u56de\u4e00\u884c\u6570\u636e\uff0c\u4e14\u8fd9\u884c\u6570\u636e\u662f\u7b2c\u4e8c\u4e2a\u8868\u7684\u4e3b\u952e\u6216\u8005\u552f\u4e00\u7d22\u5f15\uff0c\u4e14\u5fc5\u987b\u4e3anot null\uff0c\u552f\u4e00\u7d22\u5f15\u548c\u4e3b\u952e\u662f\u591a\u5217\u65f6\uff0c\u53ea\u6709\u6240\u6709\u7684\u5217\u90fd\u7528\u4f5c\u6bd4\u8f83\u65f6\u624d\u4f1a\u51fa\u73b0eq_ref<\/p>\n<p>D\uff1aref\uff1a\u4e0d\u50cfeq_ref\u90a3\u6837\u8981\u6c42\u8fde\u63a5\u987a\u5e8f\uff0c\u4e5f\u6ca1\u6709\u4e3b\u952e\u548c\u552f\u4e00\u7d22\u5f15\u7684\u8981\u6c42\uff0c\u53ea\u8981\u4f7f\u7528\u76f8\u7b49\u6761\u4ef6\u68c0\u7d22\u65f6\u5c31\u53ef\u80fd\u51fa\u73b0\uff0c\u5e38\u89c1\u4e0e\u8f85\u52a9\u7d22\u5f15\u7684\u7b49\u503c\u67e5\u627e\u3002\u6216\u8005\u591a\u5217\u4e3b\u952e\u3001\u552f\u4e00\u7d22\u5f15\u4e2d\uff0c\u4f7f\u7528\u7b2c\u4e00\u4e2a\u5217\u4e4b\u5916\u7684\u5217\u4f5c\u4e3a\u7b49\u503c\u67e5\u627e\u4e5f\u4f1a\u51fa\u73b0\uff0c\u603b\u4e4b\uff0c\u8fd4\u56de\u6570\u636e\u4e0d\u552f\u4e00\u7684\u7b49\u503c\u67e5\u627e\u5c31\u53ef\u80fd\u51fa\u73b0\u3002<\/p>\n<p>E\uff1afulltext\uff1a\u5168\u6587\u7d22\u5f15\u68c0\u7d22\uff0c\u8981\u6ce8\u610f\uff0c\u5168\u6587\u7d22\u5f15\u7684\u4f18\u5148\u7ea7\u5f88\u9ad8\uff0c\u82e5\u5168\u6587\u7d22\u5f15\u548c\u666e\u901a\u7d22\u5f15\u540c\u65f6\u5b58\u5728\u65f6\uff0cmysql\u4e0d\u7ba1\u4ee3\u4ef7\uff0c\u4f18\u5148\u9009\u62e9\u4f7f\u7528\u5168\u6587\u7d22\u5f15<\/p>\n<p>F\uff1aref_or_null\uff1a\u4e0eref\u65b9\u6cd5\u7c7b\u4f3c\uff0c\u53ea\u662f\u589e\u52a0\u4e86null\u503c\u7684\u6bd4\u8f83\u3002\u5b9e\u9645\u7528\u7684\u4e0d\u591a\u3002<\/p>\n<p>G\uff1aunique_subquery\uff1a\u7528\u4e8ewhere\u4e2d\u7684in\u5f62\u5f0f\u5b50\u67e5\u8be2\uff0c\u5b50\u67e5\u8be2\u8fd4\u56de\u4e0d\u91cd\u590d\u503c\u552f\u4e00\u503c<\/p>\n<p>H\uff1aindex_subquery\uff1a\u7528\u4e8ein\u5f62\u5f0f\u5b50\u67e5\u8be2\u4f7f\u7528\u5230\u4e86\u8f85\u52a9\u7d22\u5f15\u6216\u8005in\u5e38\u6570\u5217\u8868\uff0c\u5b50\u67e5\u8be2\u53ef\u80fd\u8fd4\u56de\u91cd\u590d\u503c\uff0c\u53ef\u4ee5\u4f7f\u7528\u7d22\u5f15\u5c06\u5b50\u67e5\u8be2\u53bb\u91cd\u3002<\/p>\n<p>I\uff1arange\uff1a\u7d22\u5f15\u8303\u56f4\u626b\u63cf\uff0c\u5e38\u89c1\u4e8e\u4f7f\u7528<code>&gt;,&lt;,is null,between ,in ,like<\/code>\u7b49\u8fd0\u7b97\u7b26\u7684\u67e5\u8be2\u4e2d\u3002<\/p>\n<p>J\uff1aindex_merge\uff1a\u8868\u793a\u67e5\u8be2\u4f7f\u7528\u4e86\u4e24\u4e2a\u4ee5\u4e0a\u7684\u7d22\u5f15\uff0c\u6700\u540e\u53d6\u4ea4\u96c6\u6216\u8005\u5e76\u96c6\uff0c\u5e38\u89c1and \uff0cor\u7684\u6761\u4ef6\u4f7f\u7528\u4e86\u4e0d\u540c\u7684\u7d22\u5f15\uff0c\u5b98\u65b9\u6392\u5e8f\u8fd9\u4e2a\u5728ref_or_null\u4e4b\u540e\uff0c\u4f46\u662f\u5b9e\u9645\u4e0a\u7531\u4e8e\u8981\u8bfb\u53d6\u6240\u4e2a\u7d22\u5f15\uff0c\u6027\u80fd\u53ef\u80fd\u5927\u90e8\u5206\u65f6\u95f4\u90fd\u4e0d\u5982range<\/p>\n<p>K\uff1aindex\uff1a\u7d22\u5f15\u5168\u8868\u626b\u63cf\uff0c\u628a\u7d22\u5f15\u4ece\u5934\u5230\u5c3e\u626b\u4e00\u904d\uff0c\u5e38\u89c1\u4e8e\u4f7f\u7528\u7d22\u5f15\u5217\u5c31\u53ef\u4ee5\u5904\u7406\u4e0d\u9700\u8981\u8bfb\u53d6\u6570\u636e\u6587\u4ef6\u7684\u67e5\u8be2\u3001\u53ef\u4ee5\u4f7f\u7528\u7d22\u5f15\u6392\u5e8f\u6216\u8005\u5206\u7ec4\u7684\u67e5\u8be2\u3002<\/p>\n<p>L\uff1aall\uff1a\u8fd9\u4e2a\u5c31\u662f\u5168\u8868\u626b\u63cf\u6570\u636e\u6587\u4ef6\uff0c\u7136\u540e\u518d\u5728server\u5c42\u8fdb\u884c\u8fc7\u6ee4\u8fd4\u56de\u7b26\u5408\u8981\u6c42\u7684\u8bb0\u5f55\u3002<\/p>\n<\/li>\n<li>\n<p>possible_keys : \u5728\u67e5\u8be2\u4e00\u6761SQL\u7684\u65f6\u5019, \u8fd9\u4e2aSQL\u6709\u53ef\u80fd\u4f1a\u4f7f\u7528\u5230\u591a\u4e2a\u7d22\u5f15,\u4f46\u662fSQL\u5728\u6267\u884c\u7684\u65f6\u5019, \u53ea\u4f1a\u9009\u62e9\u5176\u4e2d\u7684\u4e00\u4e2a\u7d22\u5f15\u6765\u4f7f\u7528<\/p>\n<p>\u67e5\u8be2\u53ef\u80fd\u4f7f\u7528\u5230\u7684\u7d22\u5f15\u90fd\u4f1a\u5728\u8fd9\u91cc\u5217\u51fa\u6765<\/p>\n<\/li>\n<li>\n<p>key : \u4e24\u4e2a\u4ee5\u4e0a\u7684\u7d22\u5f15\u79f0\u4e3a\u590d\u5408\u7d22\u5f15<\/p>\n<p>\u67e5\u8be2\u771f\u6b63\u4f7f\u7528\u5230\u7684\u7d22\u5f15\uff0cselect_type\u4e3aindex_merge\u65f6\uff0c\u8fd9\u91cc\u53ef\u80fd\u51fa\u73b0\u4e24\u4e2a\u4ee5\u4e0a\u7684\u7d22\u5f15\uff0c\u5176\u4ed6\u7684select_type\u8fd9\u91cc\u53ea\u4f1a\u51fa\u73b0\u4e00\u4e2a\u3002<\/p>\n<\/li>\n<li>\n<p>key_len<\/p>\n<p>\u7528\u4e8e\u5904\u7406\u67e5\u8be2\u7684\u7d22\u5f15\u957f\u5ea6\uff0c\u5982\u679c\u662f\u5355\u5217\u7d22\u5f15\uff0c\u90a3\u5c31\u6574\u4e2a\u7d22\u5f15\u957f\u5ea6\u7b97\u8fdb\u53bb\uff0c\u5982\u679c\u662f\u591a\u5217\u7d22\u5f15\uff0c\u90a3\u4e48\u67e5\u8be2\u4e0d\u4e00\u5b9a\u90fd\u80fd\u4f7f\u7528\u5230\u6240\u6709\u7684\u5217\uff0c\u5177\u4f53\u4f7f\u7528\u5230\u4e86\u591a\u5c11\u4e2a\u5217\u7684\u7d22\u5f15\uff0c\u8fd9\u91cc\u5c31\u4f1a\u8ba1\u7b97\u8fdb\u53bb\uff0c\u6ca1\u6709\u4f7f\u7528\u5230\u7684\u5217\uff0c\u8fd9\u91cc\u4e0d\u4f1a\u8ba1\u7b97\u8fdb\u53bb\u3002\u7559\u610f\u4e0b\u8fd9\u4e2a\u5217\u7684\u503c\uff0c\u7b97\u4e00\u4e0b\u4f60\u7684\u591a\u5217\u7d22\u5f15\u603b\u957f\u5ea6\u5c31\u77e5\u9053\u6709\u6ca1\u6709\u4f7f\u7528\u5230\u6240\u6709\u7684\u5217\u4e86\u3002\u8981\u6ce8\u610f\uff0cmysql\u7684ICP\u7279\u6027\u4f7f\u7528\u5230\u7684\u7d22\u5f15\u4e0d\u4f1a\u8ba1\u5165\u5176\u4e2d\u3002\u53e6\u5916\uff0ckey_len\u53ea\u8ba1\u7b97where\u6761\u4ef6\u7528\u5230\u7684\u7d22\u5f15\u957f\u5ea6\uff0c\u800c\u6392\u5e8f\u548c\u5206\u7ec4\u5c31\u7b97\u7528\u5230\u4e86\u7d22\u5f15\uff0c\u4e5f\u4e0d\u4f1a\u8ba1\u7b97\u5230key_len\u4e2d\u3002<\/p>\n<\/li>\n<li>\n<p>ref<\/p>\n<p>\u5982\u679c\u662f\u4f7f\u7528\u7684\u5e38\u6570\u7b49\u503c\u67e5\u8be2\uff0c\u8fd9\u91cc\u4f1a\u663e\u793aconst\uff0c\u5982\u679c\u662f\u8fde\u63a5\u67e5\u8be2\uff0c\u88ab\u9a71\u52a8\u8868\u7684\u6267\u884c\u8ba1\u5212\u8fd9\u91cc\u4f1a\u663e\u793a\u9a71\u52a8\u8868\u7684\u5173\u8054\u5b57\u6bb5\uff0c\u5982\u679c\u662f\u6761\u4ef6\u4f7f\u7528\u4e86\u8868\u8fbe\u5f0f\u6216\u8005\u51fd\u6570\uff0c\u6216\u8005\u6761\u4ef6\u5217\u53d1\u751f\u4e86\u5185\u90e8\u9690\u5f0f\u8f6c\u6362\uff0c\u8fd9\u91cc\u53ef\u80fd\u663e\u793a\u4e3afunc<\/p>\n<\/li>\n<li>\n<p>rows<\/p>\n<p>\u8fd9\u91cc\u662f\u6267\u884c\u8ba1\u5212\u4e2d\u4f30\u7b97\u7684\u626b\u63cf\u884c\u6570\uff0c\u4e0d\u662f\u7cbe\u786e\u503c<\/p>\n<\/li>\n<li>\n<p>extra<\/p>\n<\/li>\n<\/ol>\n<pre><code>\u8fd9\u4e2a\u5217\u53ef\u4ee5\u663e\u793a\u7684\u4fe1\u606f\u975e\u5e38\u591a\uff0c\u6709\u51e0\u5341\u79cd\uff0c\u5e38\u7528\u7684\u6709\n\nA\uff1adistinct\uff1a\u5728select\u90e8\u5206\u4f7f\u7528\u4e86distinc\u5173\u952e\u5b57\n\nB\uff1ano tables used\uff1a\u4e0d\u5e26from\u5b57\u53e5\u7684\u67e5\u8be2\u6216\u8005From dual\u67e5\u8be2\n\nC\uff1a\u4f7f\u7528not in()\u5f62\u5f0f\u5b50\u67e5\u8be2\u6216not exists\u8fd0\u7b97\u7b26\u7684\u8fde\u63a5\u67e5\u8be2\uff0c\u8fd9\u79cd\u53eb\u505a\u53cd\u8fde\u63a5\u3002\u5373\uff0c\u4e00\u822c\u8fde\u63a5\u67e5\u8be2\u662f\u5148\u67e5\u8be2\u5185\u8868\uff0c\u518d\u67e5\u8be2\u5916\u8868\uff0c\u53cd\u8fde\u63a5\u5c31\u662f\u5148\u67e5\u8be2\u5916\u8868\uff0c\u518d\u67e5\u8be2\u5185\u8868\u3002\n\nD\uff1ausing filesort\uff1a\u6392\u5e8f\u65f6\u65e0\u6cd5\u4f7f\u7528\u5230\u7d22\u5f15\u65f6\uff0c\u5c31\u4f1a\u51fa\u73b0\u8fd9\u4e2a\u3002\u5e38\u89c1\u4e8eorder by\u548cgroup by\u8bed\u53e5\u4e2d\n\nE\uff1ausing index\uff1a\u67e5\u8be2\u65f6\u4e0d\u9700\u8981\u56de\u8868\u67e5\u8be2\uff0c\u76f4\u63a5\u901a\u8fc7\u7d22\u5f15\u5c31\u53ef\u4ee5\u83b7\u53d6\u67e5\u8be2\u7684\u6570\u636e\u3002\n\nF\uff1ausing join buffer\uff08block nested loop\uff09\uff0cusing join buffer\uff08batched key accss\uff09\uff1a5.6.x\u4e4b\u540e\u7684\u7248\u672c\u4f18\u5316\u5173\u8054\u67e5\u8be2\u7684BNL\uff0cBKA\u7279\u6027\u3002\u4e3b\u8981\u662f\u51cf\u5c11\u5185\u8868\u7684\u5faa\u73af\u6570\u91cf\u4ee5\u53ca\u6bd4\u8f83\u987a\u5e8f\u5730\u626b\u63cf\u67e5\u8be2\u3002\n\nG\uff1ausing sort\\_union\uff0cusing\\_union\uff0cusing intersect\uff0cusing sort\\_intersection\uff1a\n\nusing intersect\uff1a\u8868\u793a\u4f7f\u7528and\u7684\u5404\u4e2a\u7d22\u5f15\u7684\u6761\u4ef6\u65f6\uff0c\u8be5\u4fe1\u606f\u8868\u793a\u662f\u4ece\u5904\u7406\u7ed3\u679c\u83b7\u53d6\u4ea4\u96c6\n\nusing union\uff1a\u8868\u793a\u4f7f\u7528or\u8fde\u63a5\u5404\u4e2a\u4f7f\u7528\u7d22\u5f15\u7684\u6761\u4ef6\u65f6\uff0c\u8be5\u4fe1\u606f\u8868\u793a\u4ece\u5904\u7406\u7ed3\u679c\u83b7\u53d6\u5e76\u96c6\n\nusing sort\\_union\u548cusing sort\\_intersection\uff1a\u4e0e\u524d\u9762\u4e24\u4e2a\u5bf9\u5e94\u7684\u7c7b\u4f3c\uff0c\u53ea\u662f\u4ed6\u4eec\u662f\u51fa\u73b0\u5728\u7528and\u548cor\u67e5\u8be2\u4fe1\u606f\u91cf\u5927\u65f6\uff0c\u5148\u67e5\u8be2\u4e3b\u952e\uff0c\u7136\u540e\u8fdb\u884c\u6392\u5e8f\u5408\u5e76\u540e\uff0c\u624d\u80fd\u8bfb\u53d6\u8bb0\u5f55\u5e76\u8fd4\u56de\u3002\n\nH\uff1ausing temporary\uff1a\u8868\u793a\u4f7f\u7528\u4e86\u4e34\u65f6\u8868\u5b58\u50a8\u4e2d\u95f4\u7ed3\u679c\u3002\u4e34\u65f6\u8868\u53ef\u4ee5\u662f\u5185\u5b58\u4e34\u65f6\u8868\u548c\u78c1\u76d8\u4e34\u65f6\u8868\uff0c\u6267\u884c\u8ba1\u5212\u4e2d\u770b\u4e0d\u51fa\u6765\uff0c\u9700\u8981\u67e5\u770bstatus\u53d8\u91cf\uff0cused\\_tmp\\_table\uff0cused\\_tmp\\_disk\\_table\u624d\u80fd\u770b\u51fa\u6765\u3002\n\nI\uff1ausing where\uff1a\u8868\u793a\u5b58\u50a8\u5f15\u64ce\u8fd4\u56de\u7684\u8bb0\u5f55\u5e76\u4e0d\u662f\u6240\u6709\u7684\u90fd\u6ee1\u8db3\u67e5\u8be2\u6761\u4ef6\uff0c\u9700\u8981\u5728server\u5c42\u8fdb\u884c\u8fc7\u6ee4\u3002\u67e5\u8be2\u6761\u4ef6\u4e2d\u5206\u4e3a\u9650\u5236\u6761\u4ef6\u548c\u68c0\u67e5\u6761\u4ef6\uff0c5.6\u4e4b\u524d\uff0c\u5b58\u50a8\u5f15\u64ce\u53ea\u80fd\u6839\u636e\u9650\u5236\u6761\u4ef6\u626b\u63cf\u6570\u636e\u5e76\u8fd4\u56de\uff0c\u7136\u540eserver\u5c42\u6839\u636e\u68c0\u67e5\u6761\u4ef6\u8fdb\u884c\u8fc7\u6ee4\u518d\u8fd4\u56de\u771f\u6b63\u7b26\u5408\u67e5\u8be2\u7684\u6570\u636e\u30025.6.x\u4e4b\u540e\u652f\u6301ICP\u7279\u6027\uff0c\u53ef\u4ee5\u628a\u68c0\u67e5\u6761\u4ef6\u4e5f\u4e0b\u63a8\u5230\u5b58\u50a8\u5f15\u64ce\u5c42\uff0c\u4e0d\u7b26\u5408\u68c0\u67e5\u6761\u4ef6\u548c\u9650\u5236\u6761\u4ef6\u7684\u6570\u636e\uff0c\u76f4\u63a5\u4e0d\u8bfb\u53d6\uff0c\u8fd9\u6837\u5c31\u5927\u5927\u51cf\u5c11\u4e86\u5b58\u50a8\u5f15\u64ce\u626b\u63cf\u7684\u8bb0\u5f55\u6570\u91cf\u3002extra\u5217\u663e\u793ausing index condition\n\nJ\uff1afirstmatch(tb\\_name)\uff1a5.6.x\u5f00\u59cb\u5f15\u5165\u7684\u4f18\u5316\u5b50\u67e5\u8be2\u7684\u65b0\u7279\u6027\u4e4b\u4e00\uff0c\u5e38\u89c1\u4e8ewhere\u5b57\u53e5\u542b\u6709in()\u7c7b\u578b\u7684\u5b50\u67e5\u8be2\u3002\u5982\u679c\u5185\u8868\u7684\u6570\u636e\u91cf\u6bd4\u8f83\u5927\uff0c\u5c31\u53ef\u80fd\u51fa\u73b0\u8fd9\u4e2a\n\nK\uff1aloosescan(m..n)\uff1a5.6.x\u4e4b\u540e\u5f15\u5165\u7684\u4f18\u5316\u5b50\u67e5\u8be2\u7684\u65b0\u7279\u6027\u4e4b\u4e00\uff0c\u5728in()\u7c7b\u578b\u7684\u5b50\u67e5\u8be2\u4e2d\uff0c\u5b50\u67e5\u8be2\u8fd4\u56de\u7684\u53ef\u80fd\u6709\u91cd\u590d\u8bb0\u5f55\u65f6\uff0c\u5c31\u53ef\u80fd\u51fa\u73b0\u8fd9\u4e2a\n<\/code><\/pre>\n<p><strong>\u9664\u4e86\u8fd9\u4e9b\u4e4b\u5916\uff0c\u8fd8\u6709\u5f88\u591a\u67e5\u8be2\u6570\u636e\u5b57\u5178\u5e93\uff0c\u6267\u884c\u8ba1\u5212\u8fc7\u7a0b\u4e2d\u5c31\u53d1\u73b0\u4e0d\u53ef\u80fd\u5b58\u5728\u7ed3\u679c\u7684\u4e00\u4e9b\u63d0\u793a\u4fe1\u606f<\/strong><\/p>\n<ol start=\"11\">\n<li>filtered<\/li>\n<\/ol>\n<pre><code>\u4f7f\u7528explain extended\u65f6\u4f1a\u51fa\u73b0\u8fd9\u4e2a\u5217\uff0c5.7\u4e4b\u540e\u7684\u7248\u672c\u9ed8\u8ba4\u5c31\u6709\u8fd9\u4e2a\u5b57\u6bb5\uff0c\u4e0d\u9700\u8981\u4f7f\u7528explain extended\u4e86\u3002\u8fd9\u4e2a\u5b57\u6bb5\u8868\u793a\u5b58\u50a8\u5f15\u64ce\u8fd4\u56de\u7684\u6570\u636e\u5728server\u5c42\u8fc7\u6ee4\u540e\uff0c\u5269\u4e0b\u591a\u5c11\u6ee1\u8db3\u67e5\u8be2\u7684\u8bb0\u5f55\u6570\u91cf\u7684\u6bd4\u4f8b\uff0c\u6ce8\u610f\u662f\u767e\u5206\u6bd4\uff0c\u4e0d\u662f\u5177\u4f53\u8bb0\u5f55\u6570\u3002\n<\/code><\/pre>\n<h2><a id=\"6%E5%85%B7%E4%BD%93%E6%85%A2%E6%9F%A5%E8%AF%A2%E4%BC%98%E5%8C%96%E7%9A%84%E6%A1%88%E4%BE%8B\" class=\"anchor\" aria-hidden=\"true\" href=\"#6%E5%85%B7%E4%BD%93%E6%85%A2%E6%9F%A5%E8%AF%A2%E4%BC%98%E5%8C%96%E7%9A%84%E6%A1%88%E4%BE%8B\"><span class=\"octicon octicon-link\"><\/span><\/a>6. \u5177\u4f53\u6162\u67e5\u8be2\u4f18\u5316\u7684\u6848\u4f8b<\/h2>\n<h3><a id=\"6-1%E5%87%BD%E6%95%B0-max%E7%9A%84%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#6-1%E5%87%BD%E6%95%B0-max%E7%9A%84%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>6.1 \u51fd\u6570 max() \u7684\u4f18\u5316<\/h3>\n<p>\u4f8b\u5982: \u67e5\u8be2\u8ba2\u5355\u7684\u6700\u540e\u652f\u4ed8\u65f6\u95f4<\/p>\n<pre><code>\tselect max(payment_date) from payment;  \n<\/code><\/pre>\n<p>\u4f18\u5316\u524d\uff1a\u00a0<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081457089.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081457089.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<blockquote>\n<p>\u67e5\u770b\u6267\u884c\u8ba1\u5212 :\u00a0<code>explain select max(payment_date) from payment;<\/code><\/p>\n<\/blockquote>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081457993.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081457993.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081459767.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081459767.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<blockquote>\n<p>\u53ef\u4ee5\u770b\u5230\u663e\u793a\u7684\u6267\u884c\u8ba1\u5212\uff0c\u5e76\u4e0d\u662f\u5f88\u9ad8\u6548\uff0c\u53ef\u4ee5\u62d6\u6162\u670d\u52a1\u5668\u7684\u6548\u7387\uff0c\u5982\u4f55\u4f18\u5316\u4e86\uff1f<\/p>\n<p>\u521b\u5efa\u7d22\u5f15 :\u00a0<code>create index inx_paydate on payment(payment_date);<\/code><\/p>\n<\/blockquote>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081459939.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081459939.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081459033.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081459033.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><strong>\u7d22\u5f15\u662f\u987a\u5e8f\u64cd\u4f5c\u7684\uff0c\u4e0d\u9700\u8981\u626b\u63cf\u8868\uff0c\u6267\u884c\u6548\u7387\u5c31\u4f1a\u6bd4\u8f83\u6052\u5b9a\uff01<\/strong><\/p>\n<h3><a id=\"6-2%E5%87%BD%E6%95%B0-count%E7%9A%84%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#6-2%E5%87%BD%E6%95%B0-count%E7%9A%84%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>6.2 \u51fd\u6570 count(*) \u7684\u4f18\u5316<\/h3>\n<p>\u9700\u6c42\uff1a\u5728\u4e00\u6761SQL\u4e2d\u540c\u65f6\u67e5\u8be22006\u5e74\u548c2007\u5e74\u7535\u5f71\u7684\u6570\u91cf<\/p>\n<p>\u9519\u8bef\u5199\u6cd5 :<\/p>\n<pre><code>select count(*) from film where release_year='2006' or release_year='2007';\n<\/code><\/pre>\n<p>\u8fd9\u79cd\u67e5\u8be2\u53ea\u80fd\u67e5\u8be2\u51fa2006\u5e74\u548c2007\u5e74\u7684\u603b\u6570\u91cf, \u4f46\u662f2006\u5e74\u548c2007\u5e74\u5206\u522b\u662f\u591a\u5c11\u65e0\u6cd5\u5224\u65ad\u51fa\u6765<\/p>\n<p>\u6b63\u786e\u7684\u7f16\u5199\u65b9\u5f0f:<\/p>\n<pre><code>SELECT release_year, COUNT(*) FROM film GROUP BY release_year HAVING release_year='2006' OR release_year='2007';\n<\/code><\/pre>\n<blockquote>\n<p>\u533a\u522b\uff1acount\uff08*\uff09\u548ccount\uff08id\uff09<\/p>\n<\/blockquote>\n<pre><code> create table t(id int);\n \n insert into t values(1),(2),(null);\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081500306.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081500306.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>count\uff08*\uff09\uff1aselect count(*)from t;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081500155.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081500155.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<pre><code>count\uff08id\uff09\uff1aselect count(id)from t;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081500912.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081500912.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<blockquote>\n<p>\u8bf4\u660e\uff1a<\/p>\n<p><strong>count\uff08id\uff09\u662f\u4e0d\u5305\u542bnull\u7684\u503c<\/strong><\/p>\n<p><strong>count\uff08*\uff09\u662f\u5305\u542bnull\u7684\u503c<\/strong><\/p>\n<\/blockquote>\n<p>\u5728\u521b\u5efa\u8868\u7684\u65f6\u5019, \u5c3d\u53ef\u80fd\u7684\u4f7f\u7528not null \u7684\u7ea6\u675f, \u4fdd\u8bc1\u6bcf\u4e00\u4e2a\u5b57\u6bb5\u9ed8\u8ba4\u503c\u4e0d\u662fnull\u503c, \u8fd9\u6837\u5728\u6267\u884ccount\u64cd\u4f5c\u7684\u65f6\u5019, \u5c31\u53ef\u4ee5\u76f4\u63a5\u7edf\u8ba1\u67d0\u4e00\u4e2a\u5b57\u6bb5\u7684\u5185\u5bb9, \u800c\u4e0d\u662f\u7edf\u8ba1\u6240\u6709\u7684\u5b57\u6bb5\u4e2a\u6570\u3002<\/p>\n<h3><a id=\"6-3%E5%AD%90%E6%9F%A5%E8%AF%A2%E7%9A%84%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#6-3%E5%AD%90%E6%9F%A5%E8%AF%A2%E7%9A%84%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>6.3 \u5b50\u67e5\u8be2\u7684\u4f18\u5316<\/h3>\n<p>\u5b50\u67e5\u8be2\u662f\u6211\u4eec\u5728\u5f00\u53d1\u8fc7\u7a0b\u4e2d\u7ecf\u5e38\u4f7f\u7528\u7684\u4e00\u79cd\u65b9\u5f0f\uff0c\u5728\u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u9700\u8981\u628a\u5b50\u67e5\u8be2\u4f18\u5316\u4e3ajoin\u67e5\u8be2\u4f46\u5728\u4f18\u5316\u662f\u9700\u8981\u6ce8\u610f\u5173\u8054\u952e\u662f\u5426\u6709\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\uff0c\u8981\u6ce8\u610f\u91cd\u590d\u6570\u636e\u3002<\/p>\n<p>\u5728\u7f16\u5199\u4ee3\u7801\u7684\u65f6\u5019, \u5982\u679c\u4f7f\u7528\u5b50\u67e5\u8be2\u53ef\u80fd\u4f1a\u6bd4\u591a\u8868\u8fde\u63a5\u67e5\u8be2\u66f4\u52a0\u7684\u7b80\u5355, \u6240\u4ee5\u5728\u5f00\u53d1\u9636\u6bb5, \u53ef\u4ee5\u4f7f\u7528\u5b50\u67e5\u8be2, \u53ea\u8981\u80fd\u591f\u6ee1\u8db3\u9700\u8981\u5c31\u53ef\u4ee5,\u4f46\u662f\u5728\u6b63\u5f0f\u4e0a\u7ebf\u7684\u5546\u4e1a\u5316\u4f7f\u7528\u7684\u65f6\u5019, \u5c3d\u53ef\u80fd\u5c06\u5b50\u67e5\u8be2\u66f4\u6539jon\u67e5\u8be2\u4f1a\u66f4\u597d\u7684\u4e00\u70b9,join\u67e5\u8be2\u7684\u6548\u7387\u8981\u6bd4\u5b50\u67e5\u8be2\u6548\u7387\u66f4\u9ad8<\/p>\n<p>\u67e5\u770b\u6211\u4eec\u6240\u521b\u5efa\u7684t\u8868\uff1a<\/p>\n<pre><code>create table t1(tid int);\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081500704.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081500704.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u521b\u5efa\u4e00\u4e2at1\u8868<\/p>\n<pre><code>create table t1(tid int);\n\ninsert into t1 values(1);\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501284.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501284.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u6211\u4eec\u8981\u8fdb\u884c\u4e00\u4e2a\u5b50\u67e5\u8be2\uff0c\u9700\u6c42\uff1a\u67e5\u8be2t\u8868\u4e2did\u5728t1\u8868\u4e2dtid\u7684\u6240\u6709\u6570\u636e\uff1b<\/p>\n<pre><code>select * from t where t.id in (select t1.tid from t1);\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501933.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501933.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u7528join\u7684\u64cd\u4f5c\u6765\u8fdb\u884c\u64cd\u4f5c<\/p>\n<pre><code>select id from t join t1 on t.id =t1.tid;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501454.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501454.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u901a\u8fc7\u4e0a\u9762\u7ed3\u679c\u6765\u770b\uff0c\u67e5\u8be2\u7684\u7ed3\u679c\u662f\u4e00\u81f4\u7684\uff0c\u6211\u4eec\u5c31\u5c06\u5b50\u67e5\u8be2\u7684\u65b9\u5f0f\u4f18\u5316\u4e3ajoin\u64cd\u4f5c\u3002<\/p>\n<p>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5728t1\u8868\u4e2d\u518d\u63d2\u5165\u4e00\u6761\u6570\u636e<\/p>\n<pre><code>insert into t1 values (1);\nselect * from t1;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501155.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501155.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u5982\u679c\u6211\u4eec\u4f7f\u7528\u5b50\u67e5\u8be2\u65b9\u5f0f\u8fdb\u884c\u67e5\u8be2\uff0c\u8fd4\u56de\u7684\u7ed3\u679c\u5c31\u662f\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501159.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501159.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u5982\u679c\u4f7f\u7528join\u65b9\u5f0f\u8fdb\u884c\u67e5\u627e\uff0c\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081501594.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081501594.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\u51fa\u73b0\u4e86\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\uff0c\u4f1a\u51fa\u73b0\u6570\u636e\u7684\u91cd\u590d\uff0c\u6211\u4eec\u4e3a\u4e86\u65b9\u5f0f\u6570\u636e\u91cd\u590d\uff0c\u4e0d\u5f97\u4e0d\u4f7f\u7528distinct\u5173\u952e\u8bcd\u8fdb\u884c\u53bb\u91cd\u64cd\u4f5c<\/p>\n<p>\u6ce8\u610f\uff1a\u8fd9\u4e2a\u4e00\u5bf9\u591a\u7684\u5173\u7cfb\u662f\u6211\u4eec\u5f00\u53d1\u8fc7\u7a0b\u4e2d\u9047\u5230\u7684\u4e00\u4e2a\u5751\uff0c\u51fa\u73b0\u6570\u636e\u91cd\u590d\uff0c\u9700\u8981\u5927\u5bb6\u6ce8\u610f\u4e00\u4e0b\u3002<\/p>\n<blockquote>\n<p>\u603b\u7ed3:\u00a0<strong>\u9700\u8981\u5c06\u5b50\u67e5\u8be2\u66f4\u4e3a join \u67e5\u8be2\uff0c\u6548\u7387\u6bd4\u8f83\u9ad8\u7684<\/strong><\/p>\n<\/blockquote>\n<h3><a id=\"6-4-group-by%E7%9A%84%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#6-4-group-by%E7%9A%84%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>6.4 group by\u7684\u4f18\u5316<\/h3>\n<p>\u9700\u6c42\uff1a\u6bcf\u4e2a\u6f14\u5458\u6240\u53c2\u6f14\u5f71\u7247\u7684\u6570\u91cf-\uff08\u5f71\u7247\u8868\u548c\u6f14\u5458\u8868\uff09<\/p>\n<pre><code>explain select actor.first_name,actor.last_name,count(*) from sakila.film_actor inner join sakila.actor using(actor_id) group by film_actor.actor_id;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502382.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502382.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u4f18\u5316\u540e\u7684SQL\uff1a<\/p>\n<pre><code>explain select actor.first_name,actor.last_name,c.cnt from sakila.actor inner join ( select actor_id,count(*) as cnt from sakila.film_actor group by actor_id) as c using(actor_id);\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502773.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502773.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u8bf4\u660e\uff1a\u4ece\u4e0a\u9762\u7684\u6267\u884c\u8ba1\u5212\u6765\u770b\uff0c\u8fd9\u79cd\u4f18\u5316\u540e\u7684\u65b9\u5f0f\u6ca1\u6709\u4f7f\u7528\u4e34\u65f6\u6587\u4ef6\u548c\u6587\u4ef6\u6392\u5e8f\u7684\u65b9\u5f0f\u4e86\uff0c\u53d6\u800c\u4ee3\u4e4b\u7684\u662f\u4f7f\u7528\u4e86\u7d22\u5f15\u3002\u67e5\u8be2\u6548\u7387\u8001\u9ad8\u4e86\u3002<\/p>\n<p>\u8fd9\u4e2a\u65f6\u5019\u6211\u4eec\u8868\u4e2d\u7684\u6570\u636e\u6bd4\u8f83\u5927\uff0c\u4f1a\u5927\u91cf\u7684\u5360\u7528IO\u64cd\u4f5c\uff0c\u4f18\u5316\u4e86sql\u6267\u884c\u7684\u6548\u7387\uff0c\u8282\u7701\u4e86\u670d\u52a1\u5668\u7684\u8d44\u6e90\uff0c\u56e0\u6b64\u6211\u4eec\u5c31\u9700\u8981\u4f18\u5316\u3002<\/p>\n<p><strong>\u6ce8\u610f\uff1a<\/strong><\/p>\n<p>mysql \u4e2dusing\u5173\u952e\u8bcd\u7684\u4f5c\u7528\uff1a\u4e5f\u5c31\u662f\u8bf4\u8981\u4f7f\u7528using\uff0c\u90a3\u4e48\u8868a\u548c\u8868b\u5fc5\u987b\u8981\u6709\u76f8\u540c\u7684\u5217\u3002<\/p>\n<p><strong>using(id) \u7c7b\u4f3c\u4e8e: on a.id = b.id<\/strong><\/p>\n<p>\u5728\u7528Join\u8fdb\u884c\u591a\u8868\u8054\u5408\u67e5\u8be2\u65f6\uff0c\u6211\u4eec\u901a\u5e38\u4f7f\u7528On\u6765\u5efa\u7acb\u4e24\u4e2a\u8868\u7684\u5173\u7cfb\u3002\u5176\u5b9e\u8fd8\u6709\u4e00\u4e2a\u66f4\u65b9\u4fbf\u7684\u5173\u952e\u5b57\uff0c\u90a3\u5c31\u662fusing\u3002<\/p>\n<p>\u5982\u679c\u4e24\u4e2a\u8868\u7684\u5173\u8054\u5b57\u6bb5\u540d\u662f\u4e00\u6837\u7684\uff0c\u5c31\u53ef\u4ee5\u4f7f\u7528Using\u6765\u5efa\u7acb\u5173\u7cfb\uff0c\u7b80\u6d01\u660e\u4e86\u3002<\/p>\n<h3><a id=\"6-5-limit%E6%9F%A5%E8%AF%A2%E7%9A%84%E4%BC%98%E5%8C%96\" class=\"anchor\" aria-hidden=\"true\" href=\"#6-5-limit%E6%9F%A5%E8%AF%A2%E7%9A%84%E4%BC%98%E5%8C%96\"><span class=\"octicon octicon-link\"><\/span><\/a>6.5 Limit\u67e5\u8be2\u7684\u4f18\u5316<\/h3>\n<blockquote>\n<p>Limit\u5e38\u7528\u4e8e\u5206\u9875\u5904\u7406\uff0c\u65f6\u957f\u4f1a\u4f34\u968forder by\u4ece\u53e5\u4f7f\u7528\uff0c\u56e0\u6b64\u5927\u591a\u65f6\u5019\u4f7f\u7528Filesorts\u8fd9\u6837\u4f1a\u9020\u6210\u5927\u91cf\u7684IO\u95ee\u9898\u3002<\/p>\n<\/blockquote>\n<p>\u9700\u6c42\uff1a\u67e5\u8be2\u5f71\u7247id\u548c\u63cf\u8ff0\u4fe1\u606f\uff0c\u5e76\u6839\u636e\u4e3b\u9898\u8fdb\u884c\u6392\u5e8f\uff0c\u53d6\u51fa\u4ece\u5e8f\u53f750\u6761\u5f00\u59cb\u76845\u6761\u6570\u636e\u3002<\/p>\n<pre><code>select film_id,description from sakila.film order by title limit 50,5;\n<\/code><\/pre>\n<p>\u5728\u67e5\u770b\u4e00\u4e0b\u5b83\u7684\u6267\u884c\u8ba1\u5212\uff1a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502778.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502778.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u5bf9\u4e8e\u8fd9\u79cd\u64cd\u4f5c\uff0c\u6211\u4eec\u8be5\u7528\u4ec0\u4e48\u6837\u7684\u4f18\u5316\u65b9\u5f0f\u4e86\uff1f<\/p>\n<ul>\n<li>\u4f18\u5316\u6b65\u9aa41\uff1a<\/li>\n<\/ul>\n<p>\u4f7f\u7528\u6709\u7d22\u5f15\u7684\u5217\u6216\u4e3b\u952e\u8fdb\u884corder by\u64cd\u4f5c\uff0c\u56e0\u4e3a\u5927\u5bb6\u77e5\u9053\uff0cinnodb\u662f\u6309\u7167\u4e3b\u952e\u7684\u903b\u8f91\u987a\u5e8f\u8fdb\u884c\u6392\u5e8f\u7684\u3002\u53ef\u4ee5\u907f\u514d\u5f88\u591a\u7684IO\u64cd\u4f5c\u3002<\/p>\n<p>\u4f18\u53161:<\/p>\n<pre><code>select film_id,description from sakila.film order by film_id limit 50,5;\n<\/code><\/pre>\n<p>\u67e5\u770b\u4e00\u4e0b\u6267\u884c\u8ba1\u5212<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502172.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502172.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u90a3\u5982\u679c\u6211\u4eec\u83b7\u53d6\u4ece500\u884c\u5f00\u59cb\u76845\u6761\u8bb0\u5f55\uff0c\u6267\u884c\u8ba1\u5212\u53c8\u662f\u4ec0\u4e48\u6837\u7684\u4e86\uff1f<\/p>\n<pre><code>explain select film_id,description from sakila.film order by film_id limit 500,5\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502241.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502241.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502264.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502264.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u968f\u7740\u6211\u4eec\u7ffb\u9875\u8d8a\u5f80\u540e\uff0cIO\u64cd\u4f5c\u4f1a\u8d8a\u6765\u8d8a\u5927\u7684\uff0c\u5982\u679c\u4e00\u4e2a\u8868\u6709\u51e0\u5343\u4e07\u884c\u6570\u636e\uff0c\u7ffb\u9875\u8d8a\u540e\u9762\uff0c\u4f1a\u8d8a\u6765\u8d8a\u6162\uff0c\u56e0\u6b64\u6211\u4eec\u8981\u8fdb\u4e00\u6b65\u7684\u6765\u4f18\u5316\u3002<\/p>\n<ul>\n<li>\u4f18\u5316\u6b65\u9aa42<\/li>\n<\/ul>\n<p>\u8bb0\u5f55\u4e0a\u6b21\u8fd4\u56de\u7684\u4e3b\u952e\uff0c \u5728\u4e0b\u6b21\u67e5\u8be2\u65f6\u4f7f\u7528\u4e3b\u952e\u8fc7\u6ee4\u3002\uff08\u8bf4\u660e\uff1a\u907f\u514d\u4e86\u6570\u636e\u91cf\u5927\u65f6\u626b\u63cf\u8fc7\u591a\u7684\u8bb0\u5f55\uff09<\/p>\n<p>\u4e0a\u6b21limit\u662f50,5\u7684\u64cd\u4f5c\uff0c\u56e0\u6b64\u6211\u4eec\u5728\u8fd9\u6b21\u4f18\u5316\u8fc7\u7a0b\u9700\u8981\u4f7f\u7528\u4e0a\u6b21\u7684\u7d22\u5f15\u8bb0\u5f55\u503c<\/p>\n<p>\u4f18\u53162:<\/p>\n<pre><code>select film_id,description from sakila.film  where film_id &gt;55 and film_id&lt;=60 order by film_id limit 0,5;\n<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081502818.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081502818.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/qn.fivedata.cn\/202206081503315.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/qn.fivedata.cn\/202206081503315.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>\u7ed3\u8bba\uff1a\u626b\u63cf\u884c\u6570\u4e0d\u53d8\uff0c\u6267\u884c\u8ba1\u5212\u662f\u5f88\u56fa\u5b9a\uff0c\u6548\u7387\u4e5f\u662f\u5f88\u56fa\u5b9a\u7684<\/p>\n<p><strong>\u6ce8\u610f\u4e8b\u9879<\/strong>\uff1a<\/p>\n<p>\u4e3b\u952e\u8981\u987a\u5e8f\u6392\u5e8f\u5e76\u8fde\u7eed\u7684\uff0c\u5982\u679c\u4e3b\u952e\u4e2d\u95f4\u7a7a\u7f3a\u4e86\u67d0\u4e00\u5217\uff0c\u6216\u8005\u67d0\u51e0\u5217\uff0c\u4f1a\u51fa\u73b0\u5217\u51fa\u6570\u636e\u4e0d\u8db35\u884c\u7684\u6570\u636e\uff1b\u5982\u679c\u4e0d\u8fde\u7eed\u7684\u60c5\u51b5\uff0c\u5efa\u7acb\u4e00\u4e2a\u9644\u52a0\u7684\u5217index_id\u5217\uff0c\u4fdd\u8bc1\u8fd9\u4e00\u5217\u6570\u636e\u8981\u81ea\u589e\u7684\uff0c\u5e76\u6dfb\u52a0\u7d22\u5f15\u5373\u53ef\u3002<\/p>\n<blockquote>\n<p>\u603b\u7ed3:<\/p>\n<p>\u5c3d\u53ef\u80fd\u907f\u514d filesorts(\u6587\u4ef6\u6392\u5e8f) \u548c row\u7684\u626b\u63cf(\u8d8a\u5c11\u8d8a\u597d)<\/p>\n<p>\u56e0\u4e3a\u8fd9\u4e24\u79cd\u64cd\u4f5c\u90fd\u4f1a\u589e\u52a0io\u64cd\u4f5c<\/p>\n<\/blockquote>\n<!--CusAds0-->\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>1. \u4e3a\u4ec0\u4e48\u8981\u8fdb\u884c\u6570\u636e\u5e93\u4f18\u5316 \u907f\u514d\u7f51\u7ad9\u9875\u9762\u51fa\u73b0\u8bbf\u95ee\u9519\u8bef \u7531\u4e8e\u6570\u636e\u5e93\u8fde\u63a5timeout\u4ea7\u751f\u9875\u97625xx\u9519\u8bef , to many connection \u7531\u4e8e\u6162\u67e5\u8be2\u9020\u6210\u9875\u9762\u65e0\u6cd5\u52a0\u8f7d : \u7531\u4e8e\u6570\u636e\u5e93\u65e0\u6cd5\u53ca\u65f6\u7684\u8fd4\u56de\u6570\u636e, \u5bfc\u81f4\u9875\u9762\u4e00\u76f4\u65e0\u6cd5\u8fd4\u56de \u7531\u4e8e\u963b\u585e\u9020\u6210\u6570\u636e\u65e0\u6cd5\u63d0\u4ea4 : \u589e\u52a0\u6570\u636e\u5e93\u7684\u7a33\u5b9a &#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0},"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/posts\/1704"}],"collection":[{"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/comments?post=1704"}],"version-history":[{"count":0,"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/posts\/1704\/revisions"}],"wp:attachment":[{"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/media?parent=1704"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/categories?post=1704"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zhang.mba\/index.php\/wp-json\/wp\/v2\/tags?post=1704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}