{"id":162771,"date":"2024-11-04T17:52:16","date_gmt":"2024-11-04T09:52:16","guid":{"rendered":"https:\/\/server.hk\/cnblog\/162771\/"},"modified":"2024-11-04T17:52:17","modified_gmt":"2024-11-04T09:52:17","slug":"%e4%ba%a4%e5%a4%a7%e6%95%b8%e6%93%9a%e5%ba%ab%ef%bc%9a%e4%bd%a0%e5%bf%85%e9%a0%88%e7%9f%a5%e9%81%93%e7%9a%84%e9%ab%98%e6%95%88%e6%9f%a5%e8%a9%a2%e6%8a%80%e5%b7%a7%ef%bc%81%ef%bc%88%e4%ba%a4%e5%a4%a7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/162771\/","title":{"rendered":"\u4ea4\u5927\u6578\u64da\u5eab\uff1a\u4f60\u5fc5\u9808\u77e5\u9053\u7684\u9ad8\u6548\u67e5\u8a62\u6280\u5de7\uff01\uff08\u4ea4\u5927\u6578\u64da\u5eab\uff09"},"content":{"rendered":"

\u4ea4\u5927\u6578\u64da\u5eab\uff1a\u4f60\u5fc5\u9808\u77e5\u9053\u7684\u9ad8\u6548\u67e5\u8a62\u6280\u5de7\uff01<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u9ad8\u6548\u67e5\u8a62\u6280\u5de7\u5c0d\u65bc\u958b\u767c\u8005\u548c\u6578\u64da\u5206\u6790\u5e2b\u4f86\u8aaa\u81f3\u95dc\u91cd\u8981\u3002\u4ea4\u5927\u6578\u64da\u5eab\u4f5c\u70ba\u4e00\u500b\u91cd\u8981\u7684\u6578\u64da\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u67e5\u8a62\u529f\u80fd\uff0c\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u7372\u53d6\u6240\u9700\u7684\u4fe1\u606f\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u4e00\u4e9b\u9ad8\u6548\u7684\u67e5\u8a62\u6280\u5de7\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u597d\u5730\u5229\u7528\u4ea4\u5927\u6578\u64da\u5eab\u3002<\/p>\n

1. \u7406\u89e3\u67e5\u8a62\u8a9e\u8a00<\/h2>\n

\u4ea4\u5927\u6578\u64da\u5eab\u901a\u5e38\u4f7f\u7528SQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u4f86\u9032\u884c\u6578\u64da\u67e5\u8a62\u3002\u719f\u6089SQL\u7684\u57fa\u672c\u8a9e\u6cd5\u662f\u9ad8\u6548\u67e5\u8a62\u7684\u7b2c\u4e00\u6b65\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u57fa\u672c\u7684SQL\u8a9e\u53e5\u793a\u4f8b\uff1a<\/p>\n

SELECT * FROM users WHERE age > 18;<\/code><\/pre>\n
\u9019\u689d\u8a9e\u53e5\u5c07\u9078\u64c7\u6240\u6709\u5e74\u9f61\u5927\u65bc18\u6b72\u7684\u7528\u6236\u3002\u7406\u89e3\u5404\u7a2eSQL\u8a9e\u53e5\u7684\u7528\u6cd5\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u66f4\u9748\u6d3b\u5730\u9032\u884c\u6578\u64da\u67e5\u8a62\u3002<\/p>\n
2. \u4f7f\u7528\u7d22\u5f15\u63d0\u9ad8\u67e5\u8a62\u6548\u7387<\/h2>\n
\u7d22\u5f15\u662f\u63d0\u9ad8\u6578\u64da\u67e5\u8a62\u6548\u7387\u7684\u91cd\u8981\u5de5\u5177\u3002\u901a\u904e\u5728\u8868\u7684\u67d0\u4e9b\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\u3002\u4ee5\u4e0b\u662f\u5275\u5efa\u7d22\u5f15\u7684\u793a\u4f8b\uff1a<\/p>\n
CREATE INDEX idx_age ON users(age);<\/code><\/pre>\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u5728\u7528\u6236\u8868\u7684\u5e74\u9f61\u5217\u4e0a\u5275\u5efa\u4e86\u4e00\u500b\u7d22\u5f15\u3002\u9019\u6a23\uff0c\u5728\u9032\u884c\u5e74\u9f61\u67e5\u8a62\u6642\uff0c\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u5feb\u5730\u5b9a\u4f4d\u5230\u76f8\u95dc\u6578\u64da\u3002<\/p>\n
3. \u9069\u7576\u4f7f\u7528JOIN\u64cd\u4f5c<\/h2>\n
\u5728\u8655\u7406\u591a\u500b\u8868\u4e4b\u9593\u7684\u6578\u64da\u6642\uff0cJOIN\u64cd\u4f5c\u662f\u5fc5\u4e0d\u53ef\u5c11\u7684\u3002\u4f7f\u7528JOIN\u53ef\u4ee5\u5c07\u4e0d\u540c\u8868\u4e2d\u7684\u6578\u64da\u7d50\u5408\u8d77\u4f86\uff0c\u5f62\u6210\u4e00\u500b\u5b8c\u6574\u7684\u6578\u64da\u96c6\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528INNER JOIN\u7684\u793a\u4f8b\uff1a<\/p>\n
SELECT users.name, orders.amount \nFROM users \nINNER JOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u7528\u6236\u7684\u59d3\u540d\u53ca\u5176\u8a02\u55ae\u91d1\u984d\u3002\u5408\u7406\u4f7f\u7528JOIN\u64cd\u4f5c\u53ef\u4ee5\u6709\u6548\u5730\u6574\u5408\u6578\u64da\uff0c\u63d0\u5347\u67e5\u8a62\u7684\u9748\u6d3b\u6027\u3002<\/p>\n
4. \u907f\u514d\u4f7f\u7528SELECT *<\/h2>\n
\u96d6\u7136\u4f7f\u7528SELECT *\u53ef\u4ee5\u65b9\u4fbf\u5730\u9078\u64c7\u6240\u6709\u5217\uff0c\u4f46\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u9019\u6a23\u7684\u505a\u6cd5\u53ef\u80fd\u6703\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\u3002\u5efa\u8b70\u7528\u6236\u660e\u78ba\u6307\u5b9a\u6240\u9700\u7684\u5217\uff0c\u4ee5\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT name, email FROM users;<\/code><\/pre>\n
\u9019\u6a23\u7684\u67e5\u8a62\u53ea\u6703\u8fd4\u56de\u7528\u6236\u7684\u59d3\u540d\u548c\u96fb\u5b50\u90f5\u4ef6\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002<\/p>\n
5. \u4f7f\u7528WHERE\u5b50\u53e5\u904e\u6ffe\u6578\u64da<\/h2>\n
\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528WHERE\u5b50\u53e5\u53ef\u4ee5\u6709\u6548\u5730\u904e\u6ffe\u4e0d\u5fc5\u8981\u7684\u6578\u64da\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528WHERE\u5b50\u53e5\u7684\u793a\u4f8b\uff1a<\/p>\n
SELECT * FROM users WHERE status = 'active';<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u53ea\u8fd4\u56de\u72c0\u614b\u70ba\u201cactive\u201d\u7684\u7528\u6236\uff0c\u6e1b\u5c11\u4e86\u6578\u64da\u7684\u8655\u7406\u91cf\u3002<\/p>\n
6. \u5b9a\u671f\u512a\u5316\u6578\u64da\u5eab<\/h2>\n
\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u53ef\u80fd\u6703\u4e0b\u964d\u3002\u5b9a\u671f\u9032\u884c\u6578\u64da\u5eab\u512a\u5316\uff0c\u5982\u91cd\u5efa\u7d22\u5f15\u548c\u6e05\u7406\u4e0d\u5fc5\u8981\u7684\u6578\u64da\uff0c\u53ef\u4ee5\u4fdd\u6301\u6578\u64da\u5eab\u7684\u9ad8\u6548\u904b\u884c\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u638c\u63e1\u9ad8\u6548\u7684\u67e5\u8a62\u6280\u5de7\u5c0d\u65bc\u4f7f\u7528\u4ea4\u5927\u6578\u64da\u5eab\u81f3\u95dc\u91cd\u8981\u3002\u901a\u904e\u7406\u89e3\u67e5\u8a62\u8a9e\u8a00\u3001\u4f7f\u7528\u7d22\u5f15\u3001\u5408\u7406\u904b\u7528JOIN\u64cd\u4f5c\u3001\u907f\u514d\u4f7f\u7528SELECT *\u3001\u4f7f\u7528WHERE\u5b50\u53e5\u904e\u6ffe\u6578\u64da\u4ee5\u53ca\u5b9a\u671f\u512a\u5316\u6578\u64da\u5eab\uff0c\u60a8\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002\u9019\u4e9b\u6280\u5de7\u4e0d\u50c5\u80fd\u5e6b\u52a9\u60a8\u66f4\u5feb\u5730\u7372\u53d6\u6240\u9700\u7684\u4fe1\u606f\uff0c\u9084\u80fd\u63d0\u5347\u6574\u9ad4\u7684\u6578\u64da\u7ba1\u7406\u6548\u7387\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5b58\u5132\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u9999\u6e2fVPS<\/a>\u6216\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\uff0c\u4ee5\u652f\u6301\u60a8\u7684\u6578\u64da\u5eab\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
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