{"id":164387,"date":"2024-11-05T07:28:26","date_gmt":"2024-11-04T23:28:26","guid":{"rendered":"https:\/\/server.hk\/cnblog\/164387\/"},"modified":"2024-11-05T07:28:27","modified_gmt":"2024-11-04T23:28:27","slug":"%e7%b2%be%e7%b0%a1%e8%aa%9e%e5%8f%a5%e5%90%a7%ef%bc%8c%e8%ae%93%e4%bd%a0%e7%9a%84mysql%e6%9b%b4%e6%9c%89%e6%95%88","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/164387\/","title":{"rendered":"\u7cbe\u7c21\u8a9e\u53e5\u5427\uff0c\u8b93\u4f60\u7684MySQL\u66f4\u6709\u6548"},"content":{"rendered":"<h1 id=\"%e7%b2%be%e7%b0%a1%e8%aa%9e%e5%8f%a5%e5%90%a7%ef%bc%8c%e8%ae%93%e4%bd%a0%e7%9a%84mysql%e6%9b%b4%e6%9c%89%e6%95%88-QmdTWtqUst\">\u7cbe\u7c21\u8a9e\u53e5\u5427\uff0c\u8b93\u4f60\u7684MySQL\u66f4\u6709\u6548<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cMySQL\u4f5c\u70ba\u4e00\u7a2e\u6d41\u884c\u7684\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u5404\u7a2e\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u5982\u4f55\u63d0\u9ad8MySQL\u7684\u6027\u80fd\u6210\u70ba\u4e86\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u7684\u91cd\u8981\u8ab2\u984c\u3002\u7cbe\u7c21\u8a9e\u53e5\u662f\u63d0\u5347MySQL\u6027\u80fd\u7684\u4e00\u500b\u6709\u6548\u65b9\u6cd5\uff0c\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u901a\u904e\u7c21\u5316SQL\u67e5\u8a62\u4f86\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6548\u7387\u3002<\/p>\n<h2 id=\"%e7%82%ba%e4%bb%80%e9%ba%bc%e8%a6%81%e7%b2%be%e7%b0%a1sql%e8%aa%9e%e5%8f%a5%ef%bc%9f-QmdTWtqUst\">\u70ba\u4ec0\u9ebc\u8981\u7cbe\u7c21SQL\u8a9e\u53e5\uff1f<\/h2>\n<p>\u7cbe\u7c21SQL\u8a9e\u53e5\u7684\u4e3b\u8981\u76ee\u7684\u662f\u6e1b\u5c11\u67e5\u8a62\u7684\u8907\u96dc\u6027\uff0c\u5f9e\u800c\u63d0\u9ad8\u57f7\u884c\u6548\u7387\u3002\u8907\u96dc\u7684\u67e5\u8a62\u4e0d\u50c5\u6703\u589e\u52a0\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff0c\u9084\u53ef\u80fd\u5c0e\u81f4\u6027\u80fd\u74f6\u9838\u3002\u4ee5\u4e0b\u662f\u5e7e\u500b\u7cbe\u7c21SQL\u8a9e\u53e5\u7684\u597d\u8655\uff1a<\/p>\n<ul>\n<li><strong>\u63d0\u9ad8\u57f7\u884c\u901f\u5ea6\uff1a<\/strong>\u7c21\u5316\u7684\u67e5\u8a62\u901a\u5e38\u80fd\u5920\u66f4\u5feb\u5730\u57f7\u884c\uff0c\u56e0\u70ba\u5b83\u5011\u9700\u8981\u8655\u7406\u7684\u6578\u64da\u91cf\u8f03\u5c11\u3002<\/li>\n<li><strong>\u964d\u4f4e\u8cc7\u6e90\u6d88\u8017\uff1a<\/strong>\u7cbe\u7c21\u7684\u67e5\u8a62\u80fd\u5920\u6e1b\u5c11CPU\u548c\u5167\u5b58\u7684\u4f7f\u7528\uff0c\u5f9e\u800c\u964d\u4f4e\u6574\u9ad4\u8cc7\u6e90\u6d88\u8017\u3002<\/li>\n<li><strong>\u6613\u65bc\u7dad\u8b77\uff1a<\/strong>\u7c21\u55ae\u7684\u67e5\u8a62\u66f4\u5bb9\u6613\u7406\u89e3\u548c\u7dad\u8b77\uff0c\u9019\u5c0d\u65bc\u5718\u968a\u5408\u4f5c\u5c24\u70ba\u91cd\u8981\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e7%b2%be%e7%b0%a1mysql%e8%aa%9e%e5%8f%a5-QmdTWtqUst\">\u5982\u4f55\u7cbe\u7c21MySQL\u8a9e\u53e5<\/h2>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8select%e6%89%80%e9%9c%80%e7%9a%84%e5%88%97-QmdTWtqUst\">1. \u4f7f\u7528SELECT\u6240\u9700\u7684\u5217<\/h3>\n<p>\u5728\u67e5\u8a62\u4e2d\uff0c\u50c5\u9078\u64c7\u5fc5\u8981\u7684\u5217\uff0c\u800c\u4e0d\u662f\u4f7f\u7528\u201cSELECT *\u201d\u3002\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u50b3\u8f38\u7684\u6578\u64da\u91cf\uff0c\u5f9e\u800c\u63d0\u9ad8\u6027\u80fd\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>-- \u4e0d\u63a8\u85a6\nSELECT * FROM users;\n\n-- \u63a8\u85a6\nSELECT id, name, email FROM users;<\/code><\/pre>\n<h3 id=\"2-%e9%81%a9%e7%95%b6%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95-QmdTWtqUst\">2. \u9069\u7576\u4f7f\u7528\u7d22\u5f15<\/h3>\n<p>\u7d22\u5f15\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u4f46\u904e\u591a\u7684\u7d22\u5f15\u6703\u5f71\u97ff\u5beb\u5165\u6027\u80fd\u3002\u56e0\u6b64\uff0c\u61c9\u6839\u64da\u67e5\u8a62\u7684\u9700\u6c42\u5408\u7406\u8a2d\u7f6e\u7d22\u5f15\u3002\u4f8b\u5982\uff0c\u5c0d\u65bc\u7d93\u5e38\u7528\u65bc\u67e5\u8a62\u7684\u5217\uff0c\u61c9\u8003\u616e\u6dfb\u52a0\u7d22\u5f15\uff1a<\/p>\n<pre><code>CREATE INDEX idx_email ON users(email);<\/code><\/pre>\n<h3 id=\"3-%e9%81%bf%e5%85%8d%e4%b8%8d%e5%bf%85%e8%a6%81%e7%9a%84join%e6%93%8d%e4%bd%9c-QmdTWtqUst\">3. \u907f\u514d\u4e0d\u5fc5\u8981\u7684JOIN\u64cd\u4f5c<\/h3>\n<p>JOIN\u64cd\u4f5c\u53ef\u4ee5\u975e\u5e38\u5f37\u5927\uff0c\u4f46\u904e\u591a\u7684JOIN\u6703\u5c0e\u81f4\u67e5\u8a62\u8b8a\u5f97\u8907\u96dc\u4e14\u7de9\u6162\u3002\u61c9\u8a72\u50c5\u5728\u5fc5\u8981\u6642\u4f7f\u7528JOIN\uff0c\u4e26\u8003\u616e\u4f7f\u7528\u5b50\u67e5\u8a62\u6216\u5176\u4ed6\u65b9\u6cd5\u4f86\u7c21\u5316\u67e5\u8a62\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>-- \u4e0d\u63a8\u85a6\nSELECT u.name, o.amount \nFROM users u \nJOIN orders o ON u.id = o.user_id \nWHERE o.status = 'completed';\n\n-- \u63a8\u85a6\nSELECT name \nFROM users \nWHERE id IN (SELECT user_id FROM orders WHERE status = 'completed');<\/code><\/pre>\n<h3 id=\"4-%e4%bd%bf%e7%94%a8limit%e9%99%90%e5%88%b6%e7%b5%90%e6%9e%9c%e9%9b%86-QmdTWtqUst\">4. \u4f7f\u7528LIMIT\u9650\u5236\u7d50\u679c\u96c6<\/h3>\n<p>\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528LIMIT\u53ef\u4ee5\u9650\u5236\u8fd4\u56de\u7684\u7d50\u679c\u96c6\u5927\u5c0f\uff0c\u9019\u5c0d\u65bc\u63d0\u9ad8\u6027\u80fd\u975e\u5e38\u6709\u6548\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT name FROM users LIMIT 10;<\/code><\/pre>\n<h3 id=\"5-%e5%ae%9a%e6%9c%9f%e6%b8%85%e7%90%86%e6%95%b8%e6%93%9a-QmdTWtqUst\">5. \u5b9a\u671f\u6e05\u7406\u6578\u64da<\/h3>\n<p>\u5b9a\u671f\u6e05\u7406\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u5eab\u7684\u5927\u5c0f\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u53ef\u4ee5\u8003\u616e\u4f7f\u7528\u5b9a\u671f\u7684\u7dad\u8b77\u4efb\u52d9\u4f86\u522a\u9664\u904e\u671f\u6216\u4e0d\u518d\u9700\u8981\u7684\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-QmdTWtqUst\">\u7d50\u8ad6<\/h2>\n<p>\u7cbe\u7c21MySQL\u8a9e\u53e5\u662f\u4e00\u500b\u6709\u6548\u7684\u63d0\u9ad8\u6578\u64da\u5eab\u6027\u80fd\u7684\u65b9\u6cd5\u3002\u901a\u904e\u9078\u64c7\u5fc5\u8981\u7684\u5217\u3001\u5408\u7406\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684JOIN\u3001\u4f7f\u7528LIMIT\u4ee5\u53ca\u5b9a\u671f\u6e05\u7406\u6578\u64da\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u5347\u67e5\u8a62\u6548\u7387\u3002\u9019\u4e0d\u50c5\u80fd\u5920\u63d0\u9ad8\u61c9\u7528\u7a0b\u5e8f\u7684\u97ff\u61c9\u901f\u5ea6\uff0c\u9084\u80fd\u964d\u4f4e\u8cc7\u6e90\u6d88\u8017\uff0c\u5f9e\u800c\u70ba\u7528\u6236\u63d0\u4f9b\u66f4\u597d\u7684\u9ad4\u9a57\u3002<\/p>\n<p>\u5982\u679c\u4f60\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u6258\u7ba1\u4f60\u7684MySQL\u6578\u64da\u5eab\uff0c\u9019\u5c07\u70ba\u4f60\u7684\u61c9\u7528\u7a0b\u5e8f\u63d0\u4f9b\u7a69\u5b9a\u548c\u5feb\u901f\u7684\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7cbe\u7c21\u8a9e\u53e5\uff0c\u63d0\u5347MySQL\u6548\u80fd\uff0c\u512a\u5316\u67e5\u8a62\u901f\u5ea6\uff0c\u6e1b\u5c11\u8cc7\u6e90\u6d88\u8017\uff0c\u8b93\u6578\u64da\u8655\u7406\u66f4\u9ad8\u6548\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-164387","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/164387","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=164387"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/164387\/revisions"}],"predecessor-version":[{"id":164388,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/164387\/revisions\/164388"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=164387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=164387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=164387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}