{"id":169997,"date":"2024-11-06T20:17:18","date_gmt":"2024-11-06T12:17:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/169997\/"},"modified":"2024-11-06T20:17:19","modified_gmt":"2024-11-06T12:17:19","slug":"%e9%82%a3%e4%ba%9b%e5%b9%b4%e6%88%91%e5%80%91%e7%b6%93%e5%b8%b8%e5%94%a0%e5%97%91%e7%9a%84sql%e5%84%aa%e5%8c%96","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/169997\/","title":{"rendered":"\u90a3\u4e9b\u5e74\u6211\u5011\u7d93\u5e38\u5520\u55d1\u7684SQL\u512a\u5316"},"content":{"rendered":"

\u90a3\u4e9b\u5e74\u6211\u5011\u7d93\u5e38\u5520\u55d1\u7684SQL\u512a\u5316<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0cSQL\u512a\u5316\u662f\u4e00\u500b\u4e0d\u53ef\u6216\u7f3a\u7684\u8a71\u984c\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u5982\u4f55\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3001\u6e1b\u5c11\u8cc7\u6e90\u6d88\u8017\u6210\u70ba\u4e86\u6bcf\u4f4d\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u9700\u8981\u9762\u5c0d\u7684\u6311\u6230\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u5e38\u898b\u7684SQL\u512a\u5316\u6280\u5de7\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u61c9\u7528\u9019\u4e9b\u6280\u8853\u3002<\/p>\n

1. \u7406\u89e3\u57f7\u884c\u8a08\u5283<\/h2>\n

\u5728\u9032\u884cSQL\u512a\u5316\u4e4b\u524d\uff0c\u9996\u5148\u9700\u8981\u4e86\u89e3\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\u3002\u57f7\u884c\u8a08\u5283\u662f\u6578\u64da\u5eab\u7cfb\u7d71\u7528\u4f86\u57f7\u884cSQL\u67e5\u8a62\u7684\u6b65\u9a5f\u548c\u7b56\u7565\u3002\u901a\u904e\u5206\u6790\u57f7\u884c\u8a08\u5283\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u8b58\u5225\u51fa\u6027\u80fd\u74f6\u9838\u3002<\/p>\n

EXPLAIN SELECT * FROM users WHERE age > 30;<\/code><\/pre>\n
\u4f7f\u7528\u4e0a\u8ff0\u8a9e\u53e5\u53ef\u4ee5\u67e5\u770b\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u4e86\u89e3\u6578\u64da\u5eab\u662f\u5982\u4f55\u8655\u7406\u9019\u500b\u67e5\u8a62\u7684\u3002\u6839\u64da\u57f7\u884c\u8a08\u5283\u7684\u7d50\u679c\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u91dd\u5c0d\u6027\u5730\u9032\u884c\u512a\u5316\u3002<\/p>\n
2. \u4f7f\u7528\u7d22\u5f15<\/h2>\n
\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u6709\u6548\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\u7279\u5225\u662f\u5728\u9032\u884c\u7be9\u9078\u3001\u6392\u5e8f\u6216\u9023\u63a5\u64cd\u4f5c\u6642\uff0c\u7d22\u5f15\u7684\u4f5c\u7528\u5c24\u70ba\u660e\u986f\u3002<\/p>\n
CREATE INDEX idx_age ON users(age);<\/code><\/pre>\n
\u7136\u800c\uff0c\u904e\u591a\u7684\u7d22\u5f15\u6703\u5f71\u97ff\u6578\u64da\u7684\u63d2\u5165\u548c\u66f4\u65b0\u6027\u80fd\uff0c\u56e0\u6b64\u5728\u5275\u5efa\u7d22\u5f15\u6642\u9700\u8981\u8b39\u614e\u8003\u91cf\u3002<\/p>\n
3. \u907f\u514dSELECT *<\/h2>\n
\u5728\u67e5\u8a62\u6642\uff0c\u4f7f\u7528SELECT *\u6703\u5c0e\u81f4\u6578\u64da\u5eab\u8fd4\u56de\u6240\u6709\u5217\uff0c\u9019\u6a23\u4e0d\u50c5\u6d6a\u8cbb\u5e36\u5bec\uff0c\u9084\u6703\u589e\u52a0\u8655\u7406\u6642\u9593\u3002\u61c9\u8a72\u660e\u78ba\u6307\u5b9a\u9700\u8981\u7684\u5217\uff0c\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002<\/p>\n
SELECT name, age FROM users WHERE age > 30;<\/code><\/pre>\n
4. \u4f7f\u7528JOIN\u800c\u975e\u5b50\u67e5\u8a62<\/h2>\n
\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528JOIN\u64cd\u4f5c\u6bd4\u4f7f\u7528\u5b50\u67e5\u8a62\u66f4\u9ad8\u6548\u3002\u5b50\u67e5\u8a62\u53ef\u80fd\u6703\u5c0e\u81f4\u591a\u6b21\u67e5\u8a62\uff0c\u800cJOIN\u5247\u53ef\u4ee5\u5728\u4e00\u6b21\u67e5\u8a62\u4e2d\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\u3002<\/p>\n
SELECT u.name, o.order_date \nFROM users u \nJOIN orders o ON u.id = o.user_id \nWHERE u.age > 30;<\/code><\/pre>\n
5. \u9650\u5236\u8fd4\u56de\u7684\u884c\u6578<\/h2>\n
\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528LIMIT\u53ef\u4ee5\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\uff0c\u9019\u5c0d\u65bc\u5927\u6578\u64da\u96c6\u7684\u67e5\u8a62\u7279\u5225\u91cd\u8981\u3002\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff0c\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u3002<\/p>\n
SELECT * FROM users WHERE age > 30 LIMIT 10;<\/code><\/pre>\n
6. \u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab<\/h2>\n
\u6578\u64da\u5eab\u7684\u6027\u80fd\u4e5f\u6703\u53d7\u5230\u788e\u7247\u5316\u7684\u5f71\u97ff\u3002\u5b9a\u671f\u9032\u884c\u6578\u64da\u5eab\u7684\u7dad\u8b77\uff0c\u5982\u91cd\u5efa\u7d22\u5f15\u548c\u66f4\u65b0\u7d71\u8a08\u4fe1\u606f\uff0c\u53ef\u4ee5\u4fdd\u6301\u6578\u64da\u5eab\u7684\u9ad8\u6548\u904b\u884c\u3002<\/p>\n
7. \u4f7f\u7528\u5408\u9069\u7684\u6578\u64da\u985e\u578b<\/h2>\n
\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u4e0d\u50c5\u53ef\u4ee5\u7bc0\u7701\u5b58\u5132\u7a7a\u9593\uff0c\u9084\u80fd\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u4f8b\u5982\uff0c\u5c0d\u65bc\u6574\u6578\u985e\u578b\u7684\u6578\u64da\uff0c\u61c9\u9078\u64c7\u5408\u9069\u7684\u6574\u6578\u985e\u578b\uff0c\u800c\u4e0d\u662f\u4f7f\u7528\u8f03\u5927\u7684\u6578\u64da\u985e\u578b\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
SQL\u512a\u5316\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\u548c\u696d\u52d9\u9700\u6c42\u7684\u8b8a\u5316\uff0c\u958b\u767c\u8005\u9700\u8981\u4e0d\u65b7\u8abf\u6574\u548c\u512a\u5316\u67e5\u8a62\u3002\u901a\u904e\u7406\u89e3\u57f7\u884c\u8a08\u5283\u3001\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u67e5\u8a62\u3001\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\u7b49\u65b9\u6cd5\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u5eab\u5728\u7a69\u5b9a\u7684\u74b0\u5883\u4e2d\u904b\u884c\uff0c\u5f9e\u800c\u9054\u5230\u6700\u4f73\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22SQL\u512a\u5316\u7684\u6280\u5de7\u8207\u7b56\u7565\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\uff0c\u8b93\u4f60\u7684\u67e5\u8a62\u66f4\u9ad8\u6548\uff0c\u6578\u64da\u8655\u7406\u66f4\u6d41\u66a2\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-169997","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/169997","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=169997"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/169997\/revisions"}],"predecessor-version":[{"id":169998,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/169997\/revisions\/169998"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=169997"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=169997"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=169997"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}