{"id":200485,"date":"2025-05-06T10:41:35","date_gmt":"2025-05-06T02:41:35","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200485\/"},"modified":"2025-05-06T10:41:35","modified_gmt":"2025-05-06T02:41:35","slug":"mysql-%e5%88%a0%e9%99%a4%e6%95%b0%e6%8d%ae%e6%97%b6%ef%bc%8c%e6%98%af%e5%90%a6%e4%bc%9a%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95%ef%bc%9f%e4%bb%a5%e8%81%94%e5%90%88%e7%b4%a2%e5%bc%95%e4%b8%ba%e4%be%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200485\/","title":{"rendered":"MySQL \u5220\u9664\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f\u4ee5\u8054\u5408\u7d22\u5f15\u4e3a\u4f8b\uff0c\u5982\u4f55\u5224\u65ad\u5220\u9664\u64cd\u4f5c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5220\u9664\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f\u4ee5\u8054\u5408\u7d22\u5f15\u4e3a\u4f8b\uff0c\u5982\u4f55\u5224\u65ad\u5220\u9664\u64cd\u4f5c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f<\/h1>\n<p>\u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u6253\u5f00\u4e86\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\u5427\uff01\u6587\u4e2d\u5185\u5bb9\u5305\u542b\u7b49\u7b49\u77e5\u8bc6\u70b9&#8230;\u5e0c\u671b\u4f60\u80fd\u5728\u9605\u8bfb\u672c\u6587\u540e\uff0c\u80fd\u771f\u771f\u5b9e\u5b9e\u5b66\u5230\u77e5\u8bc6\u6216\u8005\u5e2e\u4f60\u89e3\u51b3\u5fc3\u4e2d\u7684\u7591\u60d1\uff0c\u4e5f\u6b22\u8fce\u5927\u4f6c\u6216\u8005\u65b0\u4eba\u670b\u53cb\u4eec\u591a\u7559\u8a00\u8bc4\u8bba\uff0c\u591a\u7ed9\u5efa\u8bae\uff01\u8c22\u8c22\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241106\/1730876446672b141ebf871.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u8d70\u7d22\u5f15\uff1f<\/strong><\/p>\n<p>\u5728\u4e00\u4e2a\u5305\u542b id\u3001name\u3001age\u3001sex\u3001work \u548c city \u5b57\u6bb5\u7684\u7528\u6237\u8868\u4e2d\uff0c\u5047\u8bbe\u5b58\u5728\u8054\u5408\u7d22\u5f15 (sex, city)\u3002\u5f53\u60f3\u8981\u5220\u9664 sex=\u7537\u3001city=\u5317\u4eac \u7684\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f\u7528\u8054\u5408\u7d22\u5f15\uff1f<\/p>\n<p><strong>\u7b54\u6848\uff1a<\/strong><\/p>\n<p>\u5728 mysql \u4e2d\uff0c\u662f\u5426\u5b58\u5728\u4ee5\u4e0b\u60c5\u51b5\u4f1a\u5f71\u54cd\u7d22\u5f15\u7684\u4f7f\u7528\uff1a<\/p>\n<ul>\n<li><strong>\u7b26\u5408\u6761\u4ef6\u7684\u6570\u636e\u91cf\uff1a<\/strong>\u6d89\u53ca\u7684\u6570\u636e\u91cf\u8d85\u8fc7 20% \u65f6\uff0c\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002<\/li>\n<li><strong>\u67e5\u8be2\u7684\u7c7b\u578b\uff1a<\/strong>\u5220\u9664\u64cd\u4f5c\u5c5e\u4e8e\u6570\u636e\u4fee\u6539\u8bed\u53e5\uff0c\u800c\u4e0d\u662f\u67e5\u8be2\u8bed\u53e5\uff0c\u56e0\u6b64\u7d22\u5f15\u7684\u4f7f\u7528\u89c4\u5219\u53ef\u80fd\u4e0d\u540c\u3002<\/li>\n<\/ul>\n<p><strong>\u5b9e\u8df5\u9a8c\u8bc1\uff1a<\/strong><\/p>\n<p>\u4e0b\u9762\u662f\u5728\u8868\u4e2d\u521b\u5efa\u6570\u636e\u603b\u6761\u6570\u4e3a 1602\u3001\u7b26\u5408\u5220\u9664\u6761\u4ef6 sex=\u5973\u3001city=\u5e7f\u5dde \u7684\u6570\u636e\u6761\u6570\u4e3a 604 \u7684\u60c5\u51b5\u4e0b\u8fdb\u884c\u5220\u9664\u64cd\u4f5c\u7684 explain \u7ed3\u679c\uff1a<\/p>\n<pre>mysql&gt; explain delete from test_del_idx where sex=\"\u5973\" and city = \"\u5e7f\u5dde\";\n+----+-------------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+\n| id | select_type | table        | partitions | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra       |\n+----+-------------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+\n|  1 | DELETE      | test_del_idx | NULL       | ALL  | idx_sex_city  | NULL | NULL    | NULL | 1602 |   100.00 | Using where |\n+----+-------------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+<\/pre>\n<p>\u7ed3\u679c\u8868\u660e\uff0c\u867d\u7136\u7b26\u5408\u6761\u4ef6\u7684\u6570\u636e\u91cf\u4e0d\u8db3 20%\uff0c\u4f46\u5220\u9664\u64cd\u4f5c\u6ca1\u6709\u4f7f\u7528\u8054\u5408\u7d22\u5f15\u3002\u8fd9\u662f\u56e0\u4e3a\u5220\u9664\u64cd\u4f5c\u4e0d\u662f\u67e5\u8be2\u64cd\u4f5c\uff0c\u800c\u662f\u6570\u636e\u4fee\u6539\u64cd\u4f5c\u3002<\/p>\n<p><strong>\u7ed3\u8bba\uff1a<\/strong><\/p>\n<p>\u5728 mysql \u4e2d\uff0c\u5220\u9664\u64cd\u4f5c\u662f\u5426\u4f7f\u7528\u7d22\u5f15\u53d6\u51b3\u4e8e\u591a\u79cd\u56e0\u7d20\uff0c\u5305\u62ec\u7b26\u5408\u6761\u4ef6\u7684\u6570\u636e\u91cf\u548c\u64cd\u4f5c\u7c7b\u578b\u7b49\u3002\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u5373\u4f7f\u6d89\u53ca\u7684\u6570\u636e\u91cf\u8f83\u5c11\uff0c\u5220\u9664\u64cd\u4f5c\u4e5f\u53ef\u80fd\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n<p>\u4eca\u5929\u5173\u4e8e\u300aMySQL \u5220\u9664\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f\u4ee5\u8054\u5408\u7d22\u5f15\u4e3a\u4f8b\uff0c\u5982\u4f55\u5224\u65ad\u5220\u9664\u64cd\u4f5c\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\uff1f\u300b\u7684\u5185\u5bb9\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\uff0c\u5982\u679c\u6709\u4ec0\u4e48\u7591\u95ee\u6216\u8005\u5efa\u8bae\uff0c\u53ef\u4ee5\u5728\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e0b\u591a\u591a\u56de\u590d\u4ea4\u6d41\uff1b\u6587\u4e2d\u82e5\u6709\u4e0d\u6b63\u4e4b\u5904\uff0c\u4e5f\u5e0c\u671b\u56de\u590d\u7559\u8a00\u4ee5\u544a\u77e5\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5220\u9664\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-200485","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200485","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=200485"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200485\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200485"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200485"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200485"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}