{"id":162853,"date":"2024-11-04T18:34:19","date_gmt":"2024-11-04T10:34:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/162853\/"},"modified":"2024-11-04T18:34:19","modified_gmt":"2024-11-04T10:34:19","slug":"%e6%95%99%e4%bd%a0%e5%a6%82%e4%bd%95%e5%84%aa%e5%8c%96sql%e8%aa%9e%e5%8f%a5%e4%b8%ad%e7%9a%84%e7%89%a9%e7%90%86%e6%9f%a5%e8%a9%a2","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/162853\/","title":{"rendered":"\u6559\u4f60\u5982\u4f55\u512a\u5316SQL\u8a9e\u53e5\u4e2d\u7684\u7269\u7406\u67e5\u8a62"},"content":{"rendered":"<h1 id=\"%e6%95%99%e4%bd%a0%e5%a6%82%e4%bd%95%e5%84%aa%e5%8c%96sql%e8%aa%9e%e5%8f%a5%e4%b8%ad%e7%9a%84%e7%89%a9%e7%90%86%e6%9f%a5%e8%a9%a2-PodanYtEQv\">\u6559\u4f60\u5982\u4f55\u512a\u5316SQL\u8a9e\u53e5\u4e2d\u7684\u7269\u7406\u67e5\u8a62<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u8207\u6578\u64da\u5eab\u9032\u884c\u4ea4\u4e92\u7684\u4e3b\u8981\u5de5\u5177\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u512a\u5316SQL\u8a9e\u53e5\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u8b8a\u5f97\u8d8a\u4f86\u8d8a\u91cd\u8981\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u512a\u5316SQL\u8a9e\u53e5\u4e2d\u7684\u7269\u7406\u67e5\u8a62\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u63d0\u5347\u7cfb\u7d71\u7684\u6548\u7387\u3002<\/p>\n<h2 id=\"%e7%90%86%e8%a7%a3%e7%89%a9%e7%90%86%e6%9f%a5%e8%a9%a2-PodanYtEQv\">\u7406\u89e3\u7269\u7406\u67e5\u8a62<\/h2>\n<p>\u7269\u7406\u67e5\u8a62\u662f\u6307\u6578\u64da\u5eab\u5728\u57f7\u884cSQL\u8a9e\u53e5\u6642\uff0c\u5be6\u969b\u4f7f\u7528\u7684\u6578\u64da\u5b58\u53d6\u65b9\u6cd5\u3002\u9019\u5305\u62ec\u5982\u4f55\u9078\u64c7\u7d22\u5f15\u3001\u5982\u4f55\u8b80\u53d6\u6578\u64da\u9801\u9762\u4ee5\u53ca\u5982\u4f55\u9032\u884c\u806f\u63a5\u7b49\u3002\u512a\u5316\u7269\u7406\u67e5\u8a62\u7684\u76ee\u7684\u662f\u6e1b\u5c11\u67e5\u8a62\u57f7\u884c\u7684\u6642\u9593\u548c\u8cc7\u6e90\u6d88\u8017\u3002<\/p>\n<h2 id=\"%e5%84%aa%e5%8c%96sql%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e5%8e%9f%e5%89%87-PodanYtEQv\">\u512a\u5316SQL\u8a9e\u53e5\u7684\u57fa\u672c\u539f\u5247<\/h2>\n<ul>\n<li><strong>\u9078\u64c7\u5408\u9069\u7684\u7d22\u5f15\uff1a<\/strong>\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u95dc\u9375\u3002\u78ba\u4fdd\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u7684\u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u7279\u5225\u662f\u7528\u65bc\u904e\u6ffe\u548c\u6392\u5e8f\u7684\u5217\u3002<\/li>\n<li><strong>\u907f\u514dSELECT *\uff1a<\/strong>\u4f7f\u7528SELECT *\u6703\u5c0e\u81f4\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\uff0c\u61c9\u8a72\u660e\u78ba\u6307\u5b9a\u9700\u8981\u7684\u5217\u3002<\/li>\n<li><strong>\u4f7f\u7528JOIN\u800c\u975e\u5b50\u67e5\u8a62\uff1a<\/strong>\u5728\u8a31\u591a\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528JOIN\u53ef\u4ee5\u6bd4\u5b50\u67e5\u8a62\u66f4\u6709\u6548\u7387\uff0c\u56e0\u70ba\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u597d\u5730\u512a\u5316JOIN\u64cd\u4f5c\u3002<\/li>\n<li><strong>\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\uff1a<\/strong>\u4f7f\u7528LIMIT\u6216TOP\u4f86\u9650\u5236\u67e5\u8a62\u8fd4\u56de\u7684\u884c\u6578\uff0c\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u7684\u8655\u7406\u91cf\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%85%b7%e9%ab%94%e5%84%aa%e5%8c%96%e6%8a%80%e5%b7%a7-PodanYtEQv\">\u5177\u9ad4\u512a\u5316\u6280\u5de7<\/h2>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95-PodanYtEQv\">1. \u4f7f\u7528\u7d22\u5f15<\/h3>\n<p>\u7d22\u5f15\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u70ba\u4e00\u500b\u8868\u5efa\u7acb\u7d22\u5f15\uff1a<\/p>\n<pre><code>CREATE INDEX idx_user_name ON users (name);<\/code><\/pre>\n<p>\u9019\u6a23\uff0c\u5728\u67e5\u8a62\u7528\u6236\u540d\u6642\uff0c\u6578\u64da\u5eab\u5c07\u80fd\u5920\u66f4\u5feb\u5730\u627e\u5230\u76f8\u95dc\u8a18\u9304\u3002<\/p>\n<h3 id=\"2-%e6%9f%a5%e8%a9%a2%e9%87%8d%e5%af%ab-PodanYtEQv\">2. \u67e5\u8a62\u91cd\u5beb<\/h3>\n<p>\u6709\u6642\u5019\uff0c\u91cd\u5beb\u67e5\u8a62\u53ef\u4ee5\u63d0\u9ad8\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u5c07\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT * FROM orders WHERE customer_id IN (SELECT id FROM customers WHERE status = 'active');<\/code><\/pre>\n<p>\u91cd\u5beb\u70ba\uff1a<\/p>\n<pre><code>SELECT o.* FROM orders o JOIN customers c ON o.customer_id = c.id WHERE c.status = 'active';<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u5229\u7528JOIN\u7684\u512a\u52e2\uff0c\u6e1b\u5c11\u67e5\u8a62\u7684\u8907\u96dc\u6027\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8explain%e5%88%86%e6%9e%90%e6%9f%a5%e8%a9%a2-PodanYtEQv\">3. \u4f7f\u7528EXPLAIN\u5206\u6790\u67e5\u8a62<\/h3>\n<p>\u4f7f\u7528EXPLAIN\u8a9e\u53e5\u53ef\u4ee5\u5e6b\u52a9\u4f60\u4e86\u89e3\u6578\u64da\u5eab\u5982\u4f55\u57f7\u884c\u67e5\u8a62\u3002\u9019\u6a23\u53ef\u4ee5\u8b58\u5225\u51fa\u6027\u80fd\u74f6\u9838\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>EXPLAIN SELECT * FROM orders WHERE customer_id = 1;<\/code><\/pre>\n<p>\u901a\u904e\u5206\u6790EXPLAIN\u7684\u8f38\u51fa\uff0c\u4f60\u53ef\u4ee5\u627e\u5230\u9700\u8981\u512a\u5316\u7684\u5730\u65b9\uff0c\u4f8b\u5982\u7f3a\u5c11\u7d22\u5f15\u6216\u4e0d\u5fc5\u8981\u7684\u5168\u8868\u6383\u63cf\u3002<\/p>\n<h3 id=\"4-%e5%ae%9a%e6%9c%9f%e7%b6%ad%e8%ad%b7%e6%95%b8%e6%93%9a%e5%ba%ab-PodanYtEQv\">4. \u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab<\/h3>\n<p>\u5b9a\u671f\u9032\u884c\u6578\u64da\u5eab\u7dad\u8b77\uff0c\u5982\u91cd\u5efa\u7d22\u5f15\u548c\u66f4\u65b0\u7d71\u8a08\u4fe1\u606f\uff0c\u53ef\u4ee5\u4fdd\u6301\u67e5\u8a62\u6027\u80fd\u7684\u7a69\u5b9a\u3002\u9019\u4e9b\u64cd\u4f5c\u53ef\u4ee5\u5e6b\u52a9\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u66f4\u597d\u5730\u7406\u89e3\u6578\u64da\u7684\u5206\u4f48\u60c5\u6cc1\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-PodanYtEQv\">\u7d50\u8ad6<\/h2>\n<p>\u512a\u5316SQL\u8a9e\u53e5\u4e2d\u7684\u7269\u7406\u67e5\u8a62\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u6d89\u53ca\u5230\u591a\u65b9\u9762\u7684\u8003\u91cf\u3002\u901a\u904e\u9078\u64c7\u5408\u9069\u7684\u7d22\u5f15\u3001\u91cd\u5beb\u67e5\u8a62\u3001\u4f7f\u7528EXPLAIN\u5206\u6790\u67e5\u8a62\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u5f9e\u800c\u63d0\u5347\u6574\u9ad4\u7cfb\u7d71\u7684\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u4f60\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u89e3\u6c7a\u65b9\u6848\u4f86\u652f\u6301\u4f60\u7684\u6578\u64da\u5eab\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\uff0c\u4ee5\u7372\u5f97\u66f4\u597d\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u512a\u5316SQL\u8a9e\u53e5\u4e2d\u7684\u7269\u7406\u67e5\u8a62\uff0c\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\uff0c\u6e1b\u5c11\u57f7\u884c\u6642\u9593\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\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-162853","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162853","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=162853"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162853\/revisions"}],"predecessor-version":[{"id":162854,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162853\/revisions\/162854"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=162853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=162853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=162853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}