{"id":186010,"date":"2024-11-11T02:21:18","date_gmt":"2024-11-10T18:21:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/186010\/"},"modified":"2024-11-11T02:21:19","modified_gmt":"2024-11-10T18:21:19","slug":"%e6%95%b8%e6%93%9a%e5%ba%absql%e5%84%aa%e5%8c%96%ef%bc%9a%e6%8f%90%e5%8d%87%e6%80%a7%e8%83%bd%e5%8a%a0%e9%80%9f%e6%9f%a5%e8%a9%a2%ef%bc%88%e6%95%b8%e6%93%9a%e5%ba%absql%e8%aa%9e%e5%8f%a5%e5%84%aa","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/186010\/","title":{"rendered":"\u6578\u64da\u5eabSQL\u512a\u5316\uff1a\u63d0\u5347\u6027\u80fd\u52a0\u901f\u67e5\u8a62\uff08\u6578\u64da\u5eabsql\u8a9e\u53e5\u512a\u5316\uff09"},"content":{"rendered":"

\u6578\u64da\u5eabSQL\u512a\u5316\uff1a\u63d0\u5347\u6027\u80fd\u52a0\u901f\u67e5\u8a62\uff08\u6578\u64da\u5eabsql\u8a9e\u53e5\u512a\u5316\uff09<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u5c0d\u65bc\u61c9\u7528\u7a0b\u5e8f\u7684\u6574\u9ad4\u6548\u7387\u81f3\u95dc\u91cd\u8981\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u5982\u4f55\u512a\u5316SQL\u67e5\u8a62\u4ee5\u63d0\u5347\u6027\u80fd\u6210\u70ba\u4e86\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u9762\u81e8\u7684\u4e00\u5927\u6311\u6230\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u6578\u64da\u5eabSQL\u512a\u5316\u7684\u5e7e\u500b\u95dc\u9375\u7b56\u7565\uff0c\u5e6b\u52a9\u60a8\u52a0\u901f\u67e5\u8a62\u4e26\u63d0\u5347\u7cfb\u7d71\u6027\u80fd\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\u3002\u901a\u904e\u5206\u6790\u57f7\u884c\u8a08\u5283\uff0c\u60a8\u53ef\u4ee5\u8b58\u5225\u51fa\u6027\u80fd\u74f6\u9838\u3002\u4f8b\u5982\uff0c\u4f7f\u7528\u4ee5\u4e0bSQL\u8a9e\u53e5\u53ef\u4ee5\u67e5\u770b\u57f7\u884c\u8a08\u5283\uff1a<\/p>\n

EXPLAIN SELECT * FROM users WHERE age > 30;<\/code><\/pre>\n
\u9019\u6a23\u53ef\u4ee5\u5e6b\u52a9\u60a8\u4e86\u89e3\u6578\u64da\u5eab\u662f\u5982\u4f55\u8655\u7406\u67e5\u8a62\u7684\uff0c\u4e26\u627e\u51fa\u53ef\u80fd\u7684\u512a\u5316\u7a7a\u9593\u3002<\/p>\n
2. \u4f7f\u7528\u7d22\u5f15<\/h2>\n
\u7d22\u5f15\u662f\u63d0\u5347\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\u80fd\u5920\u6e1b\u5c11\u6578\u64da\u5eab\u9700\u8981\u6383\u63cf\u7684\u884c\u6578\u3002<\/p>\n
\u4f8b\u5982\uff0c\u5c0d\u65bc\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n
SELECT * FROM orders WHERE customer_id = 123;<\/code><\/pre>\n
\u5728customer_id\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\uff1a<\/p>\n
CREATE INDEX idx_customer_id ON orders(customer_id);<\/code><\/pre>\n
3. \u907f\u514dSELECT *<\/h2>\n
\u5728\u64b0\u5bebSQL\u67e5\u8a62\u6642\uff0c\u907f\u514d\u4f7f\u7528SELECT *\uff0c\u56e0\u70ba\u9019\u6703\u5c0e\u81f4\u6578\u64da\u5eab\u8fd4\u56de\u6240\u6709\u5217\uff0c\u589e\u52a0\u4e86\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\u548c\u8655\u7406\u6642\u9593\u3002\u76f8\u53cd\uff0c\u61c9\u8a72\u660e\u78ba\u6307\u5b9a\u6240\u9700\u7684\u5217\uff1a<\/p>\n
SELECT id, name 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\u6709\u6548\u3002JOIN\u53ef\u4ee5\u5728\u55ae\u500b\u67e5\u8a62\u4e2d\u5408\u4f75\u591a\u500b\u8868\u7684\u6578\u64da\uff0c\u901a\u5e38\u80fd\u5920\u63d0\u9ad8\u6027\u80fd\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT u.name, o.amount \nFROM users u \nJOIN orders o ON u.id = o.customer_id \nWHERE u.age > 30;<\/code><\/pre>\n
\u9019\u6a23\u7684\u67e5\u8a62\u901a\u5e38\u6bd4\u5d4c\u5957\u5b50\u67e5\u8a62\u66f4\u5feb\uff0c\u56e0\u70ba\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u8655\u7406JOIN\u64cd\u4f5c\u3002<\/p>\n
5. \u9650\u5236\u8fd4\u56de\u7684\u884c\u6578<\/h2>\n
\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528LIMIT\u5b50\u53e5\u53ef\u4ee5\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\uff0c\u9019\u5c0d\u65bc\u63d0\u9ad8\u6027\u80fd\u5c24\u5176\u91cd\u8981\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u6578\u64da\u96c6\u6642\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT * FROM products LIMIT 10;<\/code><\/pre>\n
\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff0c\u4e26\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\u3002<\/p>\n
6. \u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab<\/h2>\n
\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\u5e6b\u52a9\u4fdd\u6301\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u96a8\u8457\u6578\u64da\u7684\u589e\u9577\u548c\u8b8a\u5316\uff0c\u9019\u4e9b\u7dad\u8b77\u64cd\u4f5c\u80fd\u5920\u78ba\u4fdd\u67e5\u8a62\u7684\u9ad8\u6548\u57f7\u884c\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u6578\u64da\u5eabSQL\u512a\u5316\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u901a\u904e\u7406\u89e3\u57f7\u884c\u8a08\u5283\u3001\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u67e5\u8a62\u3001\u9078\u64c7\u5408\u9069\u7684\u67e5\u8a62\u65b9\u5f0f\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u5347\u6027\u80fd\u548c\u52a0\u901f\u67e5\u8a62\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\u7a0b\u5e8f\u4f86\u8aaa\uff0c\u9019\u4e9b\u512a\u5316\u7b56\u7565\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u89e3\u6c7a\u65b9\u6848\u4f86\u652f\u6301\u60a8\u7684\u6578\u64da\u5eab\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528\u9999\u6e2fVPS<\/a>\u6216\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":"
\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\uff0c\u900f\u904eSQL\u512a\u5316\u6280\u5de7\u52a0\u901f\u67e5\u8a62\u6548\u7387\uff0c\u8b93\u6578\u64da\u8655\u7406\u66f4\u5feb\u901f\u3001\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-186010","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186010","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=186010"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186010\/revisions"}],"predecessor-version":[{"id":186011,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186010\/revisions\/186011"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=186010"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=186010"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=186010"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}