{"id":193124,"date":"2024-11-12T20:18:19","date_gmt":"2024-11-12T12:18:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/193124\/"},"modified":"2024-11-12T20:18:20","modified_gmt":"2024-11-12T12:18:20","slug":"%e6%80%a7%e8%83%bd%e5%84%aa%e5%8c%96-mysql%e5%b8%b8%e8%a6%8bsql%e9%8c%af%e8%aa%a4%e7%94%a8%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/193124\/","title":{"rendered":"\u6027\u80fd\u512a\u5316 | MySQL\u5e38\u898bSQL\u932f\u8aa4\u7528\u6cd5"},"content":{"rendered":"

\u6027\u80fd\u512a\u5316 | MySQL\u5e38\u898bSQL\u932f\u8aa4\u7528\u6cd5<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u512a\u5316\u5c0d\u65bc\u61c9\u7528\u7a0b\u5e8f\u7684\u6574\u9ad4\u6548\u80fd\u81f3\u95dc\u91cd\u8981\u3002MySQL\u4f5c\u70ba\u4e00\u500b\u6d41\u884c\u7684\u958b\u6e90\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u5404\u7a2e\u7db2\u7ad9\u548c\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002\u7136\u800c\uff0c\u958b\u767c\u8005\u5728\u64b0\u5bebSQL\u67e5\u8a62\u6642\uff0c\u5e38\u5e38\u6703\u72af\u4e00\u4e9b\u5e38\u898b\u7684\u932f\u8aa4\uff0c\u9019\u4e9b\u932f\u8aa4\u4e0d\u50c5\u5f71\u97ff\u67e5\u8a62\u7684\u6027\u80fd\uff0c\u9084\u53ef\u80fd\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u6216\u5176\u4ed6\u554f\u984c\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u5e38\u898b\u7684SQL\u932f\u8aa4\u7528\u6cd5\u53ca\u5176\u89e3\u6c7a\u65b9\u6848\uff0c\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u512a\u5316MySQL\u6027\u80fd\u3002<\/p>\n

1. \u4e0d\u4f7f\u7528\u7d22\u5f15<\/h2>\n

\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u95dc\u9375\u5de5\u5177\u3002\u7576\u67e5\u8a62\u6d89\u53ca\u5927\u91cf\u6578\u64da\u6642\uff0c\u6c92\u6709\u7d22\u5f15\u7684\u67e5\u8a62\u53ef\u80fd\u6703\u5c0e\u81f4\u5168\u8868\u6383\u63cf\uff0c\u5f9e\u800c\u986f\u8457\u964d\u4f4e\u6027\u80fd\u3002\u958b\u767c\u8005\u61c9\u8a72\u78ba\u4fdd\u5728\u7d93\u5e38\u67e5\u8a62\u7684\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\u3002<\/p>\n

-- \u5275\u5efa\u7d22\u5f15\u7684\u7bc4\u4f8b\nCREATE INDEX idx_user_email ON users(email);\n<\/code><\/pre>\n
2. \u4f7f\u7528SELECT *<\/h2>\n
\u4f7f\u7528SELECT *\u6703\u5c0e\u81f4\u67e5\u8a62\u8fd4\u56de\u6240\u6709\u5217\uff0c\u9019\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5c0e\u81f4\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\u548c\u8655\u7406\u3002\u958b\u767c\u8005\u61c9\u8a72\u50c5\u9078\u64c7\u9700\u8981\u7684\u5217\uff0c\u4ee5\u6e1b\u5c11\u6578\u64da\u7684\u50b3\u8f38\u91cf\u3002<\/p>\n
-- \u512a\u5316\u67e5\u8a62\u7684\u7bc4\u4f8b\nSELECT id, name, email FROM users WHERE active = 1;\n<\/code><\/pre>\n
3. \u5ffd\u7565JOIN\u7684\u6027\u80fd<\/h2>\n
\u5728\u9032\u884c\u591a\u8868\u67e5\u8a62\u6642\uff0cJOIN\u64cd\u4f5c\u7684\u6027\u80fd\u53ef\u80fd\u6703\u53d7\u5230\u5f71\u97ff\u3002\u958b\u767c\u8005\u61c9\u8a72\u6ce8\u610fJOIN\u7684\u9806\u5e8f\uff0c\u4e26\u78ba\u4fdd\u5728JOIN\u7684\u5217\u4e0a\u6709\u9069\u7576\u7684\u7d22\u5f15\u3002<\/p>\n
-- \u512a\u5316JOIN\u7684\u7bc4\u4f8b\nSELECT u.name, o.amount \nFROM users u\nJOIN orders o ON u.id = o.user_id\nWHERE u.active = 1;\n<\/code><\/pre>\n
4. \u4f7f\u7528\u4e0d\u5fc5\u8981\u7684\u5b50\u67e5\u8a62<\/h2>\n
\u5b50\u67e5\u8a62\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\uff0c\u7279\u5225\u662f\u7576\u5b50\u67e5\u8a62\u8fd4\u56de\u5927\u91cf\u6578\u64da\u6642\u3002\u958b\u767c\u8005\u61c9\u8003\u616e\u4f7f\u7528JOIN\u6216\u5176\u4ed6\u65b9\u6cd5\u4f86\u66ff\u4ee3\u5b50\u67e5\u8a62\u3002<\/p>\n
-- \u4f7f\u7528JOIN\u66ff\u4ee3\u5b50\u67e5\u8a62\u7684\u7bc4\u4f8b\nSELECT u.name, (SELECT COUNT(*) FROM orders o WHERE o.user_id = u.id) AS order_count\nFROM users u;\n<\/code><\/pre>\n
5. \u5ffd\u7565\u6578\u64da\u985e\u578b<\/h2>\n
\u5728\u5275\u5efa\u8868\u6642\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u5c0d\u65bc\u6027\u80fd\u81f3\u95dc\u91cd\u8981\u3002\u4f7f\u7528\u904e\u5927\u7684\u6578\u64da\u985e\u578b\u6703\u6d6a\u8cbb\u5b58\u5132\u7a7a\u9593\uff0c\u4e26\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\u3002\u958b\u767c\u8005\u61c9\u6839\u64da\u5be6\u969b\u9700\u6c42\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u3002<\/p>\n
-- \u512a\u5316\u6578\u64da\u985e\u578b\u7684\u7bc4\u4f8b\nCREATE TABLE users (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    name VARCHAR(100),\n    email VARCHAR(255),\n    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP\n);\n<\/code><\/pre>\n
6. \u5ffd\u7565\u67e5\u8a62\u7de9\u5b58<\/h2>\n
MySQL\u63d0\u4f9b\u4e86\u67e5\u8a62\u7de9\u5b58\u529f\u80fd\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u958b\u767c\u8005\u61c9\u8a72\u6839\u64da\u61c9\u7528\u7a0b\u5e8f\u7684\u9700\u6c42\uff0c\u5408\u7406\u914d\u7f6e\u67e5\u8a62\u7de9\u5b58\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u512a\u5316MySQL\u6027\u80fd\u9700\u8981\u958b\u767c\u8005\u5c0d\u5e38\u898b\u7684SQL\u932f\u8aa4\u7528\u6cd5\u6709\u6df1\u5165\u7684\u4e86\u89e3\u3002\u901a\u904e\u6b63\u78ba\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684SELECT *\u3001\u5408\u7406\u4f7f\u7528JOIN\u3001\u6e1b\u5c11\u5b50\u67e5\u8a62\u3001\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u4ee5\u53ca\u5229\u7528\u67e5\u8a62\u7de9\u5b58\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u80fd\u7684\u61c9\u7528\u7a0b\u5e8f\uff0c\u9078\u64c7\u5408\u9069\u7684\u9999\u6e2fVPS<\/a>\u6216\u4e91\u4f3a\u670d\u5668<\/a>\u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u5c07\u6709\u52a9\u65bc\u78ba\u4fdd\u6578\u64da\u5eab\u7684\u7a69\u5b9a\u6027\u548c\u97ff\u61c9\u901f\u5ea6\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22MySQL\u6027\u80fd\u512a\u5316\u6280\u5de7\uff0c\u4e86\u89e3\u5e38\u898bSQL\u932f\u8aa4\u7528\u6cd5\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6548\u7387\uff0c\u907f\u514d\u5e38\u898b\u9677\u9631\uff0c\u78ba\u4fdd\u6700\u4f73\u6027\u80fd\u8868\u73fe\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-193124","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193124","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=193124"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193124\/revisions"}],"predecessor-version":[{"id":193125,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/193124\/revisions\/193125"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=193124"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=193124"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=193124"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}