{"id":173361,"date":"2024-11-07T17:23:29","date_gmt":"2024-11-07T09:23:29","guid":{"rendered":"https:\/\/server.hk\/cnblog\/173361\/"},"modified":"2024-11-07T17:23:30","modified_gmt":"2024-11-07T09:23:30","slug":"%e5%a6%82%e4%bd%95%e9%ab%98%e6%95%88%e9%81%8d%e6%ad%b7%e6%95%b8%e6%93%9a%e5%ba%ab%ef%bc%9asql%e7%9a%84%e5%84%aa%e5%8c%96%e6%8a%80%e5%b7%a7-sql-%e5%a6%82%e4%bd%95%e9%ab%98%e6%95%88%e9%81%8d%e6%ad%b7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/173361\/","title":{"rendered":"\u5982\u4f55\u9ad8\u6548\u904d\u6b77\u6578\u64da\u5eab\uff1aSQL\u7684\u512a\u5316\u6280\u5de7 (sql \u5982\u4f55\u9ad8\u6548\u904d\u6b77\u6578\u64da\u5eab)"},"content":{"rendered":"

\u5982\u4f55\u9ad8\u6548\u904d\u6b77\u6578\u64da\u5eab\uff1aSQL\u7684\u512a\u5316\u6280\u5de7<\/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\u7121\u8ad6\u662f\u5927\u578b\u4f01\u696d\u9084\u662f\u5c0f\u578b\u521d\u5275\u516c\u53f8\uff0c\u512a\u5316SQL\u67e5\u8a62\u4ee5\u9ad8\u6548\u904d\u6b77\u6578\u64da\u5eab\u90fd\u662f\u4e00\u9805\u5fc5\u8981\u7684\u6280\u80fd\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u6709\u6548\u7684SQL\u512a\u5316\u6280\u5de7\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u63d0\u9ad8\u6578\u64da\u5eab\u67e5\u8a62\u7684\u6027\u80fd\u3002<\/p>\n

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

\u7d22\u5f15\u662f\u63d0\u9ad8\u6578\u64da\u5eab\u67e5\u8a62\u901f\u5ea6\u7684\u95dc\u9375\u3002\u901a\u904e\u5728\u8868\u7684\u7279\u5b9a\u5217\u4e0a\u5275\u5efa\u7d22\u5f15\uff0c\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u5feb\u5730\u67e5\u627e\u548c\u6aa2\u7d22\u6578\u64da\u3002\u4ee5\u4e0b\u662f\u5275\u5efa\u7d22\u5f15\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n

CREATE INDEX index_name ON table_name (column_name);<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u6709\u4e00\u500b\u7528\u6236\u8868\uff0c\u4e26\u4e14\u7d93\u5e38\u6839\u64da\u7528\u6236\u540d\u67e5\u8a62\uff0c\u53ef\u4ee5\u9019\u6a23\u5275\u5efa\u7d22\u5f15\uff1a<\/p>\n
CREATE INDEX idx_username ON users (username);<\/code><\/pre>\n
2. \u907f\u514dSELECT *<\/h2>\n
\u4f7f\u7528\u201cSELECT *\u201d\u6703\u5c0e\u81f4\u6578\u64da\u5eab\u6aa2\u7d22\u6240\u6709\u5217\uff0c\u9019\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\u3002\u76f8\u53cd\uff0c\u61c9\u8a72\u53ea\u9078\u64c7\u9700\u8981\u7684\u5217\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT username, email FROM users WHERE id = 1;<\/code><\/pre>\n
\u9019\u6a23\u4e0d\u50c5\u6e1b\u5c11\u4e86\u6578\u64da\u50b3\u8f38\u91cf\uff0c\u9084\u63d0\u9ad8\u4e86\u67e5\u8a62\u6548\u7387\u3002<\/p>\n
3. \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\u6e1b\u5c11\u67e5\u8a62\u7684\u8ca0\u64d4\u3002\u78ba\u4fdd\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u9069\u7576\u7684\u689d\u4ef6\u4f86\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT * FROM orders WHERE order_date > '2023-01-01';<\/code><\/pre>\n
4. \u9069\u7576\u4f7f\u7528JOIN<\/h2>\n
\u5728\u591a\u500b\u8868\u4e4b\u9593\u9032\u884c\u806f\u63a5\u6642\uff0c\u61c9\u8a72\u8b39\u614e\u4f7f\u7528JOIN\u64cd\u4f5c\u3002\u78ba\u4fdd\u53ea\u806f\u63a5\u5fc5\u8981\u7684\u8868\uff0c\u4e26\u4f7f\u7528\u9069\u7576\u7684\u806f\u63a5\u985e\u578b\uff08\u5982INNER JOIN\u3001LEFT JOIN\u7b49\uff09\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT users.username, orders.amount \nFROM users \nINNER JOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n
5. \u4f7f\u7528LIMIT\u9650\u5236\u7d50\u679c\u96c6<\/h2>\n
\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528LIMIT\u5b50\u53e5\u53ef\u4ee5\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\uff0c\u9019\u5c0d\u65bc\u9700\u8981\u5206\u9801\u986f\u793a\u7684\u61c9\u7528\u7a0b\u5e8f\u7279\u5225\u6709\u7528\u3002\u4f8b\u5982\uff1a<\/p>\n
SELECT * FROM products LIMIT 10 OFFSET 20;<\/code><\/pre>\n
\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u5eab\u7684\u8ca0\u64d4\uff0c\u4e26\u63d0\u9ad8\u97ff\u61c9\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\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u9019\u4e9b\u64cd\u4f5c\u53ef\u4ee5\u5e6b\u52a9\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u66f4\u597d\u5730\u7406\u89e3\u6578\u64da\u7684\u5206\u4f48\u60c5\u6cc1\uff0c\u5f9e\u800c\u512a\u5316\u67e5\u8a62\u8a08\u5283\u3002<\/p>\n
7. \u4f7f\u7528\u67e5\u8a62\u5206\u6790\u5de5\u5177<\/h2>\n
\u8a31\u591a\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u63d0\u4f9b\u67e5\u8a62\u5206\u6790\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u8b58\u5225\u6027\u80fd\u74f6\u9838\u3002\u901a\u904e\u5206\u6790\u67e5\u8a62\u57f7\u884c\u8a08\u5283\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u627e\u5230\u9700\u8981\u512a\u5316\u7684\u90e8\u5206\uff0c\u4e26\u9032\u884c\u76f8\u61c9\u7684\u8abf\u6574\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u9ad8\u6548\u904d\u6b77\u6578\u64da\u5eab\u662f\u63d0\u5347\u61c9\u7528\u7a0b\u5e8f\u6027\u80fd\u7684\u95dc\u9375\u3002\u901a\u904e\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u5217\u9078\u64c7\u3001\u9069\u7576\u4f7f\u7528WHERE\u5b50\u53e5\u548cJOIN\u64cd\u4f5c\u3001\u9650\u5236\u7d50\u679c\u96c6\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8SQL\u67e5\u8a62\u7684\u6548\u7387\u3002\u9019\u4e9b\u6280\u5de7\u4e0d\u50c5\u80fd\u5e6b\u52a9\u958b\u767c\u8005\u512a\u5316\u73fe\u6709\u7684\u67e5\u8a62\uff0c\u9084\u80fd\u70ba\u672a\u4f86\u7684\u6578\u64da\u5eab\u8a2d\u8a08\u63d0\u4f9b\u6307\u5c0e\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4f86\u652f\u6301\u60a8\u7684\u6578\u64da\u5eab\u9700\u6c42\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u5e6b\u52a9\u60a8\u8f15\u9b06\u7ba1\u7406\u548c\u512a\u5316\u60a8\u7684\u6578\u64da\u5eab\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u638c\u63e1SQL\u512a\u5316\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u5eab\u904d\u6b77\u6548\u7387\uff0c\u5feb\u901f\u67e5\u8a62\u8207\u6578\u64da\u8655\u7406\uff0c\u52a9\u4f60\u8f15\u9b06\u7ba1\u7406\u6d77\u91cf\u6578\u64da\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-173361","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/173361","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=173361"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/173361\/revisions"}],"predecessor-version":[{"id":173362,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/173361\/revisions\/173362"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=173361"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=173361"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=173361"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}