{"id":200300,"date":"2025-05-06T10:11:59","date_gmt":"2025-05-06T02:11:59","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200300\/"},"modified":"2025-05-06T10:11:59","modified_gmt":"2025-05-06T02:11:59","slug":"%e4%b8%ba%e4%bb%80%e4%b9%88-select-from-new_pool-where-chlid-news_top-%e7%9a%84-explain-%e7%bb%93%e6%9e%9c%e4%b8%ad-indextype-%e4%b8%ba-all","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200300\/","title":{"rendered":"\u4e3a\u4ec0\u4e48 `select * from new_pool where chlid != \\”news_top\\” && chlid != \\”news_ent\\” limit 1;` \u7684 `EXPLAIN` \u7ed3\u679c\u4e2d `indexType` \u4e3a `ALL`\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

\u4e3a\u4ec0\u4e48 `select * from new_pool where chlid != \\”news_top\\” && chlid != \\”news_ent\\” limit 1;` \u7684 `EXPLAIN` \u7ed3\u679c\u4e2d `indexType` \u4e3a `ALL`\uff1f<\/h1>\n

\u7f16\u7a0b\u5e76\u4e0d\u662f\u4e00\u4e2a\u673a\u68b0\u6027\u7684\u5de5\u4f5c\uff0c\u800c\u662f\u9700\u8981\u6709\u601d\u8003\uff0c\u6709\u521b\u65b0\u7684\u5de5\u4f5c\uff0c\u8bed\u6cd5\u662f\u56fa\u5b9a\u7684\uff0c\u4f46\u89e3\u51b3\u95ee\u9898\u7684\u601d\u8def\u5219\u662f\u4f9d\u9760\u4eba\u7684\u601d\u7ef4\uff0c\u8fd9\u5c31\u9700\u8981\u6211\u4eec\u575a\u6301\u5b66\u4e60\u548c\u66f4\u65b0\u81ea\u5df1\u7684\u77e5\u8bc6\u3002\u4eca\u5929\u4e3b\u673a\u5b9d\u8d1d\u5c31\u6574\u7406\u5206\u4eab\u300a\u4e3a\u4ec0\u4e48 `select * from new_pool where chlid != \\”news_top\\” && chlid != \\”news_ent\\” limit 1;` \u7684 `EXPLAIN` \u7ed3\u679c\u4e2d `indexType` \u4e3a `ALL`\uff1f\u300b\uff0c\u6587\u7ae0\u8bb2\u89e3\u7684\u77e5\u8bc6\u70b9\u4e3b\u8981\u5305\u62ec\uff0c\u5982\u679c\u4f60\u5bf9\u6570\u636e\u5e93\u65b9\u9762\u7684\u77e5\u8bc6\u70b9\u611f\u5174\u8da3\uff0c\u5c31\u4e0d\u8981\u9519\u8fc7\u4e3b\u673a\u5b9d\u8d1d\uff0c\u5728\u8fd9\u53ef\u4ee5\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u52a9\u529b\u5f00\u53d1\u80fd\u529b\u7684\u63d0\u5347\u3002<\/p>\n

<\/p>\n

MySQL EXPLAIN \u4e2d indexType \u4e3a All \u7684\u539f\u56e0<\/strong><\/p>\n

\u5728 MySQL \u4e2d\uff0cEXPLAIN \u8bed\u53e5\u53ef\u4ee5\u7528\u6765\u5206\u6790\u67e5\u8be2\u8ba1\u5212\uff0c\u5176\u4e2d indexType \u5217\u8868\u793a\u4e86\u67e5\u8be2\u6240\u4f7f\u7528\u7684\u7d22\u5f15\u7c7b\u578b\u3002\u7136\u800c\uff0c\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u67e5\u8be2\u53ef\u80fd\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\uff0c\u800c\u662f\u8fdb\u884c\u5168\u8868\u626b\u63cf\uff0c\u6b64\u65f6 indexType \u4f1a\u663e\u793a\u4e3a ALL\u3002<\/p>\n

\u8fd9\u7bc7\u6587\u7ae0\u5c31\u5c06\u63a2\u8ba8\u4e00\u4e2a\u793a\u4f8b\u67e5\u8be2\uff0c\u5373 select * from new_pool where chlid != “news_top” && chlid != “news_ent” limit 1;\uff0c\u5e76\u89e3\u91ca\u4e3a\u4ec0\u4e48\u5b83\u7684 indexType \u4e3a ALL\u3002<\/p>\n

\u95ee\u9898\u5206\u6790<\/strong><\/p>\n

\u793a\u4f8b\u67e5\u8be2\u7684 new_pool \u8868\u5177\u6709\u4e00\u4e2a\u591a\u5217\u7d22\u5f15 (chlid, indexType, pubtime)\u3002\u4f46\u5f53\u6267\u884c EXPLAIN \u65f6\uff0c\u53d1\u73b0\u5b83\u7684 indexType \u5374\u662f ALL\u3002<\/p>\n

\u539f\u56e0<\/strong><\/p>\n

MySQL \u4f18\u5316\u5668\u4f1a\u5c06\u4f7f\u7528\u7d22\u5f15\u4e0e\u5168\u8868\u626b\u63cf\u7684\u6210\u672c\u8fdb\u884c\u6bd4\u8f83\u3002\u5982\u679c\u4f7f\u7528\u7d22\u5f15\u7684\u6210\u672c\u8d85\u8fc7\u4e00\u5b9a\u9608\u503c\uff0c\u4f18\u5316\u5668\u5c31\u4f1a\u9009\u62e9\u8fdb\u884c\u5168\u8868\u626b\u63cf\u3002<\/p>\n

\u5728\u793a\u4f8b\u67e5\u8be2\u4e2d\uff0c\u7531\u4e8e != \u64cd\u4f5c\u7b26\u7684\u6210\u672c\u5f88\u9ad8\uff0c\u4f7f\u7528\u7d22\u5f15\u7684\u6210\u672c\u53ef\u80fd\u8d85\u8fc7\u4e86\u5168\u8868\u626b\u63cf\u7684\u6210\u672c\u3002\u56e0\u6b64\uff0c\u4f18\u5316\u5668\u9009\u62e9\u4e86\u5168\u8868\u626b\u63cf\uff0c\u5bfc\u81f4 indexType \u663e\u793a\u4e3a ALL\u3002<\/p>\n

\u4eca\u5929\u5173\u4e8e\u300a\u4e3a\u4ec0\u4e48 `select * from new_pool where chlid != \\”news_top\\” && chlid != \\”news_ent\\” limit 1;` \u7684 `EXPLAIN` \u7ed3\u679c\u4e2d `indexType` \u4e3a `ALL`\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

\n
\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"

\u4e3a\u4ec0\u4e48 `select * fr...<\/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-200300","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200300","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=200300"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200300\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}