{"id":76696,"date":"2024-10-16T09:03:18","date_gmt":"2024-10-16T01:03:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/76696\/"},"modified":"2024-10-16T09:03:19","modified_gmt":"2024-10-16T01:03:19","slug":"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%adexplain%e7%9a%84%e4%bd%bf%e7%94%a8%e5%8f%8a%e5%85%b6%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85%e8%a9%b3%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/76696\/","title":{"rendered":"MySQL\u6578\u64da\u5eab\u4e2dEXPLAIN\u7684\u4f7f\u7528\u53ca\u5176\u6ce8\u610f\u4e8b\u9805\u8a73\u89e3"},"content":{"rendered":"<h1 id=\"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%adexplain%e7%9a%84%e4%bd%bf%e7%94%a8%e5%8f%8a%e5%85%b6%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85%e8%a9%b3%e8%a7%a3-fWdXacJZhP\">MySQL\u6578\u64da\u5eab\u4e2dEXPLAIN\u7684\u4f7f\u7528\u53ca\u5176\u6ce8\u610f\u4e8b\u9805\u8a73\u89e3<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u6027\u80fd\u512a\u5316\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u800cMySQL\u4f5c\u70ba\u4e00\u500b\u6d41\u884c\u7684\u958b\u6e90\u6578\u64da\u5eab\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u5de5\u5177\u4f86\u5e6b\u52a9\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u9032\u884c\u6027\u80fd\u5206\u6790\u3002\u5176\u4e2d\uff0c<code>EXPLAIN<\/code>\u8a9e\u53e5\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u7406\u89e3\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u512a\u5316\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afexplain%ef%bc%9f-fWdXacJZhP\">\u4ec0\u9ebc\u662fEXPLAIN\uff1f<\/h2>\n<p><code>EXPLAIN<\/code>\u8a9e\u53e5\u7528\u65bc\u986f\u793aMySQL\u57f7\u884c\u67e5\u8a62\u7684\u8a08\u5283\u3002\u7576\u4f60\u5728\u67e5\u8a62\u524d\u52a0\u4e0a<code>EXPLAIN<\/code>\uff0cMySQL\u6703\u8fd4\u56de\u4e00\u500b\u8868\u683c\uff0c\u986f\u793a\u67e5\u8a62\u7684\u57f7\u884c\u6b65\u9a5f\uff0c\u5305\u62ec\u4f7f\u7528\u7684\u7d22\u5f15\u3001\u8868\u7684\u806f\u63a5\u9806\u5e8f\u3001\u9810\u8a08\u7684\u884c\u6578\u7b49\u4fe1\u606f\u3002<\/p>\n<h2 id=\"explain%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-fWdXacJZhP\">EXPLAIN\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>\u4f7f\u7528<code>EXPLAIN<\/code>\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>EXPLAIN SELECT * FROM your_table WHERE your_condition;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u6703\u8fd4\u56de\u4e00\u500b\u8868\u683c\uff0c\u986f\u793aMySQL\u5982\u4f55\u57f7\u884c\u9019\u500b\u67e5\u8a62\u3002<\/p>\n<h2 id=\"explain%e7%9a%84%e8%bc%b8%e5%87%ba%e8%a7%a3%e8%ae%80-fWdXacJZhP\">EXPLAIN\u7684\u8f38\u51fa\u89e3\u8b80<\/h2>\n<p>EXPLAIN\u7684\u8f38\u51fa\u5305\u542b\u591a\u500b\u91cd\u8981\u7684\u5217\uff0c\u4ee5\u4e0b\u662f\u4e00\u4e9b\u95dc\u9375\u5217\u7684\u89e3\u91cb\uff1a<\/p>\n<ul>\n<li><strong>id<\/strong>\uff1a\u67e5\u8a62\u7684\u8b58\u5225\u78bc\uff0c\u5c0d\u65bc\u8907\u96dc\u67e5\u8a62\uff0c\u9019\u500b\u503c\u53ef\u4ee5\u5e6b\u52a9\u4f60\u7406\u89e3\u67e5\u8a62\u7684\u57f7\u884c\u9806\u5e8f\u3002<\/li>\n<li><strong>select_type<\/strong>\uff1a\u67e5\u8a62\u7684\u985e\u578b\uff0c\u4f8b\u5982<code>SIMPLE<\/code>\uff08\u7c21\u55ae\u67e5\u8a62\uff09\u3001<code>PRIMARY<\/code>\uff08\u4e3b\u67e5\u8a62\uff09\u7b49\u3002<\/li>\n<li><strong>table<\/strong>\uff1a\u986f\u793a\u6b63\u5728\u8a2a\u554f\u7684\u8868\u540d\u3002<\/li>\n<li><strong>type<\/strong>\uff1a\u986f\u793a\u806f\u63a5\u985e\u578b\uff0c\u5f9e<code>ALL<\/code>\uff08\u5168\u8868\u6383\u63cf\uff09\u5230<code>const<\/code>\uff08\u5e38\u6578\u67e5\u8a62\uff09\u7b49\uff0c\u8d8a\u63a5\u8fd1<code>const<\/code>\uff0c\u6027\u80fd\u8d8a\u597d\u3002<\/li>\n<li><strong>possible_keys<\/strong>\uff1a\u986f\u793a\u53ef\u80fd\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>key<\/strong>\uff1a\u5be6\u969b\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>rows<\/strong>\uff1a\u9810\u8a08\u9700\u8981\u6383\u63cf\u7684\u884c\u6578\u3002<\/li>\n<li><strong>Extra<\/strong>\uff1a\u63d0\u4f9b\u984d\u5916\u7684\u4fe1\u606f\uff0c\u4f8b\u5982\u662f\u5426\u4f7f\u7528\u4e86<code>Using temporary<\/code>\u6216<code>Using filesort<\/code>\u7b49\u3002<\/li>\n<\/ul>\n<h2 id=\"%e4%bd%bf%e7%94%a8explain%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-fWdXacJZhP\">\u4f7f\u7528EXPLAIN\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528<code>EXPLAIN<\/code>\u6642\uff0c\u6709\u5e7e\u500b\u6ce8\u610f\u4e8b\u9805\u9700\u8981\u8003\u616e\uff1a<\/p>\n<ul>\n<li><strong>\u67e5\u8a62\u7684\u8907\u96dc\u6027<\/strong>\uff1a\u5c0d\u65bc\u8907\u96dc\u7684\u67e5\u8a62\uff0c<code>EXPLAIN<\/code>\u7684\u8f38\u51fa\u53ef\u80fd\u6703\u8b8a\u5f97\u96e3\u4ee5\u7406\u89e3\u3002\u5efa\u8b70\u5c07\u67e5\u8a62\u62c6\u5206\u70ba\u66f4\u7c21\u55ae\u7684\u90e8\u5206\u9032\u884c\u5206\u6790\u3002<\/li>\n<li><strong>\u6578\u64da\u91cf\u7684\u5f71\u97ff<\/strong>\uff1a\u5728\u5c0f\u6578\u64da\u96c6\u4e0a\u6e2c\u8a66\u67e5\u8a62\u6027\u80fd\u53ef\u80fd\u4e0d\u5177\u4ee3\u8868\u6027\u3002\u61c9\u5728\u63a5\u8fd1\u5be6\u969b\u751f\u7522\u74b0\u5883\u7684\u6578\u64da\u96c6\u4e0a\u9032\u884c\u6e2c\u8a66\u3002<\/li>\n<li><strong>\u7d22\u5f15\u7684\u4f7f\u7528<\/strong>\uff1a\u78ba\u4fdd\u67e5\u8a62\u4e2d\u4f7f\u7528\u4e86\u9069\u7576\u7684\u7d22\u5f15\u3002<code>EXPLAIN<\/code>\u7684\u8f38\u51fa\u53ef\u4ee5\u5e6b\u52a9\u4f60\u5224\u65b7\u662f\u5426\u9700\u8981\u6dfb\u52a0\u6216\u4fee\u6539\u7d22\u5f15\u3002<\/li>\n<li><strong>\u6301\u7e8c\u76e3\u63a7<\/strong>\uff1a\u96a8\u8457\u6578\u64da\u7684\u589e\u9577\u548c\u67e5\u8a62\u6a21\u5f0f\u7684\u8b8a\u5316\uff0c\u5b9a\u671f\u4f7f\u7528<code>EXPLAIN<\/code>\u4f86\u6aa2\u67e5\u67e5\u8a62\u6027\u80fd\u662f\u5fc5\u8981\u7684\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-fWdXacJZhP\">\u7d50\u8ad6<\/h2>\n<p>\u4f7f\u7528<code>EXPLAIN<\/code>\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u6df1\u5165\u7406\u89e3MySQL\u67e5\u8a62\u7684\u57f7\u884c\u904e\u7a0b\uff0c\u5f9e\u800c\u9032\u884c\u6709\u6548\u7684\u6027\u80fd\u512a\u5316\u3002\u901a\u904e\u5206\u6790<code>EXPLAIN<\/code>\u7684\u8f38\u51fa\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u8b58\u5225\u6f5b\u5728\u7684\u6027\u80fd\u74f6\u9838\uff0c\u4e26\u6839\u64da\u9700\u8981\u8abf\u6574\u67e5\u8a62\u6216\u7d22\u5f15\u8a2d\u7f6e\u3002\u5c0d\u65bc\u5e0c\u671b\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\u7684\u7528\u6236\u4f86\u8aaa\uff0c\u638c\u63e1<code>EXPLAIN<\/code>\u7684\u4f7f\u7528\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u6211\u5011\u7684<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u670d\u52d9\uff0c\u70ba\u60a8\u7684\u61c9\u7528\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u63a2\u8a0eMySQL\u6578\u64da\u5eab\u4e2dEXPLAIN\u7684\u4f7f\u7528\u65b9\u6cd5\u53ca\u6ce8\u610f\u4e8b\u9805\uff0c\u5e6b\u52a9\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-76696","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76696","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=76696"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76696\/revisions"}],"predecessor-version":[{"id":76697,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76696\/revisions\/76697"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=76696"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=76696"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=76696"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}