{"id":199664,"date":"2025-05-06T09:05:27","date_gmt":"2025-05-06T01:05:27","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199664\/"},"modified":"2025-05-06T09:05:27","modified_gmt":"2025-05-06T01:05:27","slug":"%e5%8f%af%e4%bb%a5%e5%af%b9%e4%b8%a4%e4%b8%aa%e5%88%97%e8%bf%9b%e8%a1%8c%e5%88%86%e7%bb%84%e5%90%97","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199664\/","title":{"rendered":"\u53ef\u4ee5\u5bf9\u4e24\u4e2a\u5217\u8fdb\u884c\u5206\u7ec4\u5417?"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>\u53ef\u4ee5\u5bf9\u4e24\u4e2a\u5217\u8fdb\u884c\u5206\u7ec4\u5417?<\/h1>\n<p>\u76ee\u524d\u4e3b\u673a\u5b9d\u8d1d\u4e0a\u5df2\u7ecf\u6709\u5f88\u591a\u5173\u4e8e\u7684\u6587\u7ae0\u4e86\uff0c\u81ea\u5df1\u5728\u521d\u6b21\u9605\u8bfb\u8fd9\u4e9b\u6587\u7ae0\u4e2d\uff0c\u4e5f\u89c1\u8bc6\u5230\u4e86\u5f88\u591a\u5b66\u4e60\u601d\u8def\uff1b\u90a3\u4e48\u672c\u6587\uff0c\u4e5f\u5e0c\u671b\u80fd\u5e2e\u52a9\u5230\u5927\u5bb6\uff0c\u5982\u679c\u9605\u8bfb\u5b8c\u540e\u771f\u7684\u5bf9\u4f60\u5b66\u4e60\u6709\u5e2e\u52a9\uff0c\u6b22\u8fce\u52a8\u52a8\u624b\u6307\uff0c\u8bc4\u8bba\u7559\u8a00\u5e76\u5206\u4eab~<\/p>\n<p>\u6807\u9898\uff1a\u4f7f\u7528GROUP BY\u5b9e\u73b0\u591a\u6761\u4ef6\u5206\u7ec4\u7684\u793a\u4f8b<\/p>\n<p>\u5728SQL\u67e5\u8be2\u4e2d\uff0cGROUP BY\u8bed\u53e5\u901a\u5e38\u7528\u4e8e\u5c06\u6570\u636e\u6309\u7167\u7279\u5b9a\u5217\u8fdb\u884c\u5206\u7ec4\uff0c\u5e76\u5bf9\u6bcf\u4e2a\u5206\u7ec4\u8fdb\u884c\u805a\u5408\u64cd\u4f5c\u3002\u7136\u800c\uff0c\u6709\u65f6\u5019\u6211\u4eec\u9700\u8981\u540c\u65f6\u6ee1\u8db3\u4e24\u4e2a\u6761\u4ef6\u8fdb\u884c\u5206\u7ec4\uff0c\u90a3\u4e48\u662f\u5426\u53ef\u4ee5\u5728GROUP BY\u8bed\u53e5\u4e2d\u4f7f\u7528\u591a\u4e2a\u6761\u4ef6\u5462\uff1f\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u901a\u8fc7\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u6765\u89e3\u7b54\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n<p>\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u540d\u4e3a&#8221;employees&#8221;\u7684\u6570\u636e\u8868\uff0c\u5176\u4e2d\u5305\u542b\u5458\u5de5\u7684\u4fe1\u606f\uff0c\u5305\u62ec\u59d3\u540d\u3001\u6240\u5c5e\u90e8\u95e8\u548c\u5de5\u8d44\u3002\u73b0\u5728\u6211\u4eec\u9700\u8981\u6309\u7167\u90e8\u95e8\u548c\u6027\u522b\u5bf9\u5458\u5de5\u8fdb\u884c\u5206\u7ec4\uff0c\u5e76\u8ba1\u7b97\u6bcf\u4e2a\u7ec4\u7684\u5e73\u5747\u5de5\u8d44\u3002<\/p>\n<p>\u9996\u5148\uff0c\u8ba9\u6211\u4eec\u521b\u5efa\u4e00\u4e2a\u793a\u4f8b\u6570\u636e\u8868\u5e76\u63d2\u5165\u4e00\u4e9b\u6570\u636e\uff1a<\/p>\n<pre>CREATE TABLE employees (\n  name VARCHAR(50),\n  department VARCHAR(50),\n  gender VARCHAR(10),\n  salary DECIMAL(10, 2)\n);\n\nINSERT INTO employees VALUES\n  ('\u5f20\u4e09', '\u9500\u552e\u90e8', '\u7537', 5000),\n  ('\u674e\u56db', '\u9500\u552e\u90e8', '\u7537', 5500),\n  ('\u738b\u4e94', '\u9500\u552e\u90e8', '\u5973', 4800),\n  ('\u8d75\u516d', '\u8d22\u52a1\u90e8', '\u5973', 6000),\n  ('\u5218\u4e03', '\u8d22\u52a1\u90e8', '\u7537', 6500),\n  ('\u9648\u516b', '\u6280\u672f\u90e8', '\u7537', 7000),\n  ('\u8bb8\u4e5d', '\u6280\u672f\u90e8', '\u5973', 5500);<\/pre>\n<p>\u73b0\u5728\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\u8bed\u53e5\u6765\u5b9e\u73b0\u6309\u7167\u90e8\u95e8\u548c\u6027\u522b\u8fdb\u884c\u5206\u7ec4\uff0c\u5e76\u8ba1\u7b97\u5e73\u5747\u5de5\u8d44\uff1a<\/p>\n<pre>SELECT department, gender, AVG(salary) AS average_salary\nFROM employees\nGROUP BY department, gender;<\/pre>\n<p>\u4e0a\u8ff0\u67e5\u8be2\u8bed\u53e5\u4e2d\u7684GROUP 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5500.00<\/pre>\n<p>\u4ece\u7ed3\u679c\u4e2d\u53ef\u4ee5\u770b\u51fa\uff0c\u6570\u636e\u9996\u5148\u6309\u7167&#8221;\u90e8\u95e8&#8221;\u5b57\u6bb5\u8fdb\u884c\u5206\u7ec4\uff0c\u7136\u540e\u5728\u6bcf\u4e2a\u90e8\u95e8\u5185\u518d\u6309\u7167&#8221;\u6027\u522b&#8221;\u5b57\u6bb5\u8fdb\u884c\u5206\u7ec4\u3002\u8fd9\u6837\u6211\u4eec\u5c31\u5b9e\u73b0\u4e86\u4f7f\u7528\u591a\u4e2a\u6761\u4ef6\u8fdb\u884c\u5206\u7ec4\u7684\u9700\u6c42\u3002<\/p>\n<p>\u603b\u7ed3\u8d77\u6765\uff0c\u6211\u4eec\u53ef\u4ee5\u5728GROUP BY\u8bed\u53e5\u4e2d\u4f7f\u7528\u591a\u4e2a\u6761\u4ef6\u8fdb\u884c\u5206\u7ec4\u3002\u901a\u8fc7\u5728GROUP BY\u5b50\u53e5\u4e2d\u4f7f\u7528\u591a\u4e2a\u5b57\u6bb5\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06\u6570\u636e\u6309\u7167\u8fd9\u4e9b\u5b57\u6bb5\u7684\u7ec4\u5408\u8fdb\u884c\u5206\u7ec4\uff0c\u5e76\u5bf9\u6bcf\u4e2a\u7ec4\u8fdb\u884c\u805a\u5408\u64cd\u4f5c\u3002\u5728\u4e0a\u8ff0\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u5c55\u793a\u4e86\u5982\u4f55\u4f7f\u7528GROUP 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<\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>\u53ef\u4ee5\u5bf9\u4e24\u4e2a\u5217\u8fdb\u884c\u5206\u7ec4\u5417? 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