{"id":158813,"date":"2024-11-03T05:05:27","date_gmt":"2024-11-02T21:05:27","guid":{"rendered":"https:\/\/server.hk\/cnblog\/158813\/"},"modified":"2024-11-03T05:05:28","modified_gmt":"2024-11-02T21:05:28","slug":"%e9%97%9c%e6%96%bcsql%e5%84%aa%e5%8c%96%e7%9a%84%e4%b8%80%e4%ba%9b%e6%80%9d%e6%83%b3%e5%92%8c%e5%8e%9f%e5%89%87","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/158813\/","title":{"rendered":"\u95dc\u65bcSQL\u512a\u5316\u7684\u4e00\u4e9b\u601d\u60f3\u548c\u539f\u5247"},"content":{"rendered":"

\u95dc\u65bcSQL\u512a\u5316\u7684\u4e00\u4e9b\u601d\u60f3\u548c\u539f\u5247<\/h1>\n

\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u8207\u6578\u64da\u5eab\u9032\u884c\u4ea4\u4e92\u7684\u4e3b\u8981\u5de5\u5177\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0cSQL\u67e5\u8a62\u7684\u6027\u80fd\u512a\u5316\u8b8a\u5f97\u8d8a\u4f86\u8d8a\u91cd\u8981\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9bSQL\u512a\u5316\u7684\u57fa\u672c\u601d\u60f3\u548c\u539f\u5247\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u63d0\u9ad8\u6578\u64da\u5eab\u67e5\u8a62\u7684\u6548\u7387\u3002<\/p>\n

1. \u7406\u89e3\u67e5\u8a62\u8a08\u5283<\/h2>\n

\u5728\u9032\u884cSQL\u512a\u5316\u4e4b\u524d\uff0c\u9996\u5148\u9700\u8981\u4e86\u89e3\u67e5\u8a62\u8a08\u5283\u3002\u67e5\u8a62\u8a08\u5283\u662f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff08DBMS\uff09\u7528\u4f86\u57f7\u884cSQL\u67e5\u8a62\u7684\u6b65\u9a5f\u3002\u4f7f\u7528EXPLAIN\u8a9e\u53e5\u53ef\u4ee5\u67e5\u770b\u67e5\u8a62\u8a08\u5283\uff0c\u9019\u6709\u52a9\u65bc\u8b58\u5225\u6f5b\u5728\u7684\u6027\u80fd\u74f6\u9838\u3002<\/p>\n

EXPLAIN SELECT * FROM users WHERE age > 30;<\/code><\/pre>\n
\u901a\u904e\u5206\u6790\u67e5\u8a62\u8a08\u5283\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u4e86\u89e3\u6578\u64da\u5eab\u662f\u5982\u4f55\u8655\u7406\u67e5\u8a62\u7684\uff0c\u4e26\u6839\u64da\u9700\u8981\u9032\u884c\u8abf\u6574\u3002<\/p>\n
2. \u4f7f\u7528\u7d22\u5f15<\/h2>\n
\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u95dc\u9375\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
2.1 \u5275\u5efa\u7d22\u5f15\u7684\u793a\u4f8b<\/h3>\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\u616e\u3002<\/p>\n
3. \u907f\u514dSELECT *<\/h2>\n
\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528SELECT *\u6703\u5c0e\u81f4\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\uff0c\u7279\u5225\u662f\u5728\u8868\u4e2d\u6709\u5927\u91cf\u5217\u6642\u3002\u61c9\u8a72\u660e\u78ba\u6307\u5b9a\u6240\u9700\u7684\u5217\uff0c\u4ee5\u6e1b\u5c11\u6578\u64da\u7684\u50b3\u8f38\u91cf\u548c\u8655\u7406\u6642\u9593\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\u6709\u6548\u3002JOIN\u53ef\u4ee5\u5728\u55ae\u500b\u67e5\u8a62\u4e2d\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\uff0c\u800c\u5b50\u67e5\u8a62\u5247\u53ef\u80fd\u5c0e\u81f4\u591a\u6b21\u67e5\u8a62\uff0c\u5f9e\u800c\u589e\u52a0\u57f7\u884c\u6642\u9593\u3002<\/p>\n
4.1 JOIN\u7684\u793a\u4f8b<\/h3>\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. \u512a\u5316WHERE\u5b50\u53e5<\/h2>\n
\u5728WHERE\u5b50\u53e5\u4e2d\u4f7f\u7528\u9069\u7576\u7684\u689d\u4ef6\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u61c9\u907f\u514d\u4f7f\u7528\u4e0d\u5fc5\u8981\u7684\u8a08\u7b97\u6216\u51fd\u6578\uff0c\u56e0\u70ba\u9019\u6703\u5c0e\u81f4\u5168\u8868\u6383\u63cf\u3002<\/p>\n
SELECT * FROM users WHERE age > 30 AND status = 'active';<\/code><\/pre>\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\u4fdd\u6301\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u9019\u4e9b\u64cd\u4f5c\u6709\u52a9\u65bc\u78ba\u4fdd\u67e5\u8a62\u8a08\u5283\u7684\u6709\u6548\u6027\uff0c\u4e26\u63d0\u9ad8\u6574\u9ad4\u6027\u80fd\u3002<\/p>\n
7. \u6e2c\u8a66\u548c\u76e3\u63a7<\/h2>\n
\u6700\u5f8c\uff0c\u6301\u7e8c\u6e2c\u8a66\u548c\u76e3\u63a7SQL\u67e5\u8a62\u7684\u6027\u80fd\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u4f7f\u7528\u6027\u80fd\u76e3\u63a7\u5de5\u5177\u53ef\u4ee5\u5e6b\u52a9\u8b58\u5225\u6162\u67e5\u8a62\uff0c\u4e26\u63d0\u4f9b\u512a\u5316\u5efa\u8b70\u3002<\/p>\n
\u7e3d\u7d50<\/h1>\n
SQL\u512a\u5316\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u6d89\u53ca\u591a\u7a2e\u6280\u8853\u548c\u7b56\u7565\u3002\u901a\u904e\u7406\u89e3\u67e5\u8a62\u8a08\u5283\u3001\u4f7f\u7528\u7d22\u5f15\u3001\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u67e5\u8a62\u3001\u512a\u5316WHERE\u5b50\u53e5\u4ee5\u53ca\u5b9a\u671f\u7dad\u8b77\u6578\u64da\u5eab\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684 VPS<\/a> \u6216 \u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u5eab\u904b\u884c\u5728\u6700\u4f73\u74b0\u5883\u4e2d\uff0c\u5f9e\u800c\u9054\u5230\u6700\u4f73\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22SQL\u512a\u5316\u7684\u95dc\u9375\u601d\u60f3\u548c\u539f\u5247\uff0c\u63d0\u5347\u67e5\u8a62\u6548\u7387\uff0c\u6e1b\u5c11\u8cc7\u6e90\u6d88\u8017\uff0c\u5be6\u73fe\u6578\u64da\u5eab\u6027\u80fd\u7684\u6700\u4f73\u5316\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-158813","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/158813","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=158813"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/158813\/revisions"}],"predecessor-version":[{"id":158814,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/158813\/revisions\/158814"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=158813"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=158813"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=158813"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}