{"id":186562,"date":"2024-11-11T06:57:19","date_gmt":"2024-11-10T22:57:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/186562\/"},"modified":"2024-11-11T06:57:20","modified_gmt":"2024-11-10T22:57:20","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e9%ab%98%e6%95%88%e6%9f%a5%e8%a9%a2%e6%8a%80%e5%b7%a7%ef%bc%9a%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e8%a1%a8%e5%84%aa%e5%8c%96%e7%9a%84%e6%96%b9%e6%b3%95%ef%bc%88%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/186562\/","title":{"rendered":"\u6578\u64da\u5eab\u9ad8\u6548\u67e5\u8a62\u6280\u5de7\uff1a\u806f\u5408\u67e5\u8a62\u8868\u512a\u5316\u7684\u65b9\u6cd5\uff08\u6578\u64da\u5eab\u8868\u806f\u5408\u67e5\u8a62\uff09"},"content":{"rendered":"<h1 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e9%ab%98%e6%95%88%e6%9f%a5%e8%a9%a2%e6%8a%80%e5%b7%a7%ef%bc%9a%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e8%a1%a8%e5%84%aa%e5%8c%96%e7%9a%84%e6%96%b9%e6%b3%95%ef%bc%88%e6%95%b8-OcjUPyoWNU\">\u6578\u64da\u5eab\u9ad8\u6548\u67e5\u8a62\u6280\u5de7\uff1a\u806f\u5408\u67e5\u8a62\u8868\u512a\u5316\u7684\u65b9\u6cd5\uff08\u6578\u64da\u5eab\u8868\u806f\u5408\u67e5\u8a62\uff09<\/h1>\n<p>\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\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\uff0c\u5982\u4f55\u9ad8\u6548\u5730\u67e5\u8a62\u6578\u64da\u6210\u70ba\u4e86\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u9762\u81e8\u7684\u4e00\u5927\u6311\u6230\u3002\u806f\u5408\u67e5\u8a62\uff08JOIN\uff09\u662f\u6578\u64da\u5eab\u4e2d\u5e38\u7528\u7684\u67e5\u8a62\u65b9\u5f0f\u4e4b\u4e00\uff0c\u901a\u904e\u5c07\u591a\u500b\u8868\u4e2d\u7684\u6578\u64da\u7d50\u5408\u8d77\u4f86\uff0c\u80fd\u5920\u63d0\u4f9b\u66f4\u8c50\u5bcc\u7684\u4fe1\u606f\u3002\u7136\u800c\uff0c\u806f\u5408\u67e5\u8a62\u7684\u6027\u80fd\u512a\u5316\u537b\u5f80\u5f80\u88ab\u5ffd\u8996\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u4e00\u4e9b\u6709\u6548\u7684\u806f\u5408\u67e5\u8a62\u8868\u512a\u5316\u65b9\u6cd5\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u63d0\u5347\u6578\u64da\u5eab\u67e5\u8a62\u7684\u6548\u7387\u3002<\/p>\n<h2 id=\"%e7%90%86%e8%a7%a3%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-OcjUPyoWNU\">\u7406\u89e3\u806f\u5408\u67e5\u8a62\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u806f\u5408\u67e5\u8a62\u662f\u6307\u5728SQL\u8a9e\u53e5\u4e2d\uff0c\u901a\u904e\u95dc\u806f\u4e0d\u540c\u7684\u8868\u4f86\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\u3002\u5e38\u898b\u7684\u806f\u5408\u67e5\u8a62\u985e\u578b\u5305\u62ec\u5167\u806f\u63a5\uff08INNER JOIN\uff09\u3001\u5916\u806f\u63a5\uff08OUTER JOIN\uff09\u3001\u4ea4\u53c9\u806f\u63a5\uff08CROSS JOIN\uff09\u7b49\u3002\u6bcf\u7a2e\u806f\u63a5\u65b9\u5f0f\u90fd\u6709\u5176\u7279\u5b9a\u7684\u7528\u9014\u548c\u6027\u80fd\u7279\u9ede\u3002<\/p>\n<h2 id=\"%e5%84%aa%e5%8c%96%e8%81%af%e5%90%88%e6%9f%a5%e8%a9%a2%e7%9a%84%e6%8a%80%e5%b7%a7-OcjUPyoWNU\">\u512a\u5316\u806f\u5408\u67e5\u8a62\u7684\u6280\u5de7<\/h2>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95-OcjUPyoWNU\">1. \u4f7f\u7528\u7d22\u5f15<\/h3>\n<p>\u7d22\u5f15\u662f\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u7684\u95dc\u9375\u3002\u5c0d\u65bc\u53c3\u8207\u806f\u5408\u67e5\u8a62\u7684\u8868\uff0c\u61c9\u8a72\u5728\u806f\u63a5\u5b57\u6bb5\u4e0a\u5275\u5efa\u7d22\u5f15\u3002\u9019\u6a23\u53ef\u4ee5\u986f\u8457\u6e1b\u5c11\u67e5\u8a62\u6642\u7684\u6383\u63cf\u6642\u9593\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6709\u5169\u500b\u8868\uff1a<code>users<\/code>\u548c<code>orders<\/code>\uff0c\u5982\u679c\u6211\u5011\u7d93\u5e38\u9700\u8981\u6839\u64da\u7528\u6236ID\u4f86\u67e5\u8a62\u8a02\u55ae\uff0c\u5247\u61c9\u5728<code>orders.user_id<\/code>\u4e0a\u5275\u5efa\u7d22\u5f15\u3002<\/p>\n<pre><code>CREATE INDEX idx_user_id ON orders(user_id);<\/code><\/pre>\n<h3 id=\"2-%e9%81%bf%e5%85%8d%e4%b8%8d%e5%bf%85%e8%a6%81%e7%9a%84%e8%81%af%e6%8e%a5-OcjUPyoWNU\">2. \u907f\u514d\u4e0d\u5fc5\u8981\u7684\u806f\u63a5<\/h3>\n<p>\u5728\u64b0\u5beb\u67e5\u8a62\u6642\uff0c\u61c9\u8a72\u4ed4\u7d30\u8003\u616e\u662f\u5426\u6240\u6709\u7684\u806f\u63a5\u90fd\u662f\u5fc5\u8981\u7684\u3002\u904e\u591a\u7684\u806f\u63a5\u4e0d\u50c5\u6703\u589e\u52a0\u67e5\u8a62\u7684\u8907\u96dc\u6027\uff0c\u9084\u6703\u5f71\u97ff\u6027\u80fd\u3002\u53ef\u4ee5\u901a\u904e\u5206\u6790\u696d\u52d9\u9700\u6c42\uff0c\u78ba\u5b9a\u54ea\u4e9b\u8868\u662f\u5fc5\u9808\u7684\uff0c\u54ea\u4e9b\u53ef\u4ee5\u7701\u7565\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e9%81%a9%e7%95%b6%e7%9a%84%e8%81%af%e6%8e%a5%e9%a1%9e%e5%9e%8b-OcjUPyoWNU\">3. \u4f7f\u7528\u9069\u7576\u7684\u806f\u63a5\u985e\u578b<\/h3>\n<p>\u6839\u64da\u5be6\u969b\u9700\u6c42\u9078\u64c7\u5408\u9069\u7684\u806f\u63a5\u985e\u578b\u3002\u4f8b\u5982\uff0c\u5167\u806f\u63a5\u901a\u5e38\u6bd4\u5916\u806f\u63a5\u6027\u80fd\u66f4\u597d\uff0c\u56e0\u70ba\u5b83\u53ea\u8fd4\u56de\u5339\u914d\u7684\u884c\u3002\u5982\u679c\u4e0d\u9700\u8981\u8fd4\u56de\u6240\u6709\u884c\uff0c\u5247\u61c9\u512a\u5148\u8003\u616e\u4f7f\u7528\u5167\u806f\u63a5\u3002<\/p>\n<pre><code>SELECT users.name, orders.amount \nFROM users \nINNER JOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n<h3 id=\"4-%e9%99%90%e5%88%b6%e8%bf%94%e5%9b%9e%e7%9a%84%e5%88%97-OcjUPyoWNU\">4. \u9650\u5236\u8fd4\u56de\u7684\u5217<\/h3>\n<p>\u5728\u67e5\u8a62\u4e2d\uff0c\u53ea\u9078\u64c7\u9700\u8981\u7684\u5217\uff0c\u800c\u4e0d\u662f\u4f7f\u7528<code>*<\/code>\u4f86\u9078\u64c7\u6240\u6709\u5217\u3002\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u7684\u91cf\uff0c\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002<\/p>\n<pre><code>SELECT users.name, orders.amount \nFROM users \nINNER JOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n<h3 id=\"5-%e4%bd%bf%e7%94%a8%e5%ad%90%e6%9f%a5%e8%a9%a2%e5%92%8ccte-OcjUPyoWNU\">5. \u4f7f\u7528\u5b50\u67e5\u8a62\u548cCTE<\/h3>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528\u5b50\u67e5\u8a62\u6216\u516c\u5171\u8868\u8868\u9054\u5f0f\uff08CTE\uff09\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u7684\u53ef\u8b80\u6027\u548c\u6027\u80fd\u3002\u9019\u4e9b\u6280\u8853\u53ef\u4ee5\u5e6b\u52a9\u5c07\u8907\u96dc\u7684\u67e5\u8a62\u5206\u89e3\u70ba\u66f4\u7c21\u55ae\u7684\u90e8\u5206\uff0c\u5f9e\u800c\u63d0\u9ad8\u57f7\u884c\u6548\u7387\u3002<\/p>\n<pre><code>WITH UserOrders AS (\n    SELECT user_id, SUM(amount) AS total_amount \n    FROM orders \n    GROUP BY user_id\n)\nSELECT users.name, UserOrders.total_amount \nFROM users \nJOIN UserOrders ON users.id = UserOrders.user_id;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-OcjUPyoWNU\">\u7d50\u8ad6<\/h2>\n<p>\u512a\u5316\u6578\u64da\u5eab\u7684\u806f\u5408\u67e5\u8a62\u4e0d\u50c5\u80fd\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u9084\u80fd\u6539\u5584\u6574\u9ad4\u7cfb\u7d71\u7684\u97ff\u61c9\u901f\u5ea6\u3002\u901a\u904e\u5408\u7406\u4f7f\u7528\u7d22\u5f15\u3001\u9078\u64c7\u5408\u9069\u7684\u806f\u63a5\u985e\u578b\u3001\u9650\u5236\u8fd4\u56de\u7684\u5217\u4ee5\u53ca\u5229\u7528\u5b50\u67e5\u8a62\u548cCTE\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u6709\u6548\u5730\u63d0\u5347\u6578\u64da\u5eab\u7684\u67e5\u8a62\u6548\u7387\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u9019\u4e9b\u6280\u5de7\u5c07\u8b8a\u5f97\u8d8a\u4f86\u8d8a\u91cd\u8981\uff0c\u5e6b\u52a9\u4f01\u696d\u5728\u6fc0\u70c8\u7684\u5e02\u5834\u7af6\u722d\u4e2d\u4fdd\u6301\u512a\u52e2\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u95dc\u65bc\u6578\u64da\u5eab\u6027\u80fd\u512a\u5316\u7684\u8cc7\u8a0a\uff0c\u6216\u5c0b\u627e\u5408\u9069\u7684 <a 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