{"id":76530,"date":"2024-10-16T07:29:16","date_gmt":"2024-10-15T23:29:16","guid":{"rendered":"https:\/\/server.hk\/cnblog\/76530\/"},"modified":"2024-10-16T07:29:17","modified_gmt":"2024-10-15T23:29:17","slug":"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e5%b0%87%e5%a4%9a%e6%a2%9d%e8%a8%98%e9%8c%84%e7%9a%84%e5%96%ae%e5%80%8b%e5%ad%97%e6%ae%b5%e5%90%88%e4%bd%b5%e6%88%90%e4%b8%80%e6%a2%9d%e8%a8%98%e9%8c%84","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/76530\/","title":{"rendered":"MySQL\u6578\u64da\u5eab\u5c07\u591a\u689d\u8a18\u9304\u7684\u55ae\u500b\u5b57\u6bb5\u5408\u4f75\u6210\u4e00\u689d\u8a18\u9304"},"content":{"rendered":"<h1 id=\"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e5%b0%87%e5%a4%9a%e6%a2%9d%e8%a8%98%e9%8c%84%e7%9a%84%e5%96%ae%e5%80%8b%e5%ad%97%e6%ae%b5%e5%90%88%e4%bd%b5%e6%88%90%e4%b8%80%e6%a2%9d%e8%a8%98%e9%8c%84-qgAvQyLcdq\">MySQL\u6578\u64da\u5eab\u5c07\u591a\u689d\u8a18\u9304\u7684\u55ae\u500b\u5b57\u6bb5\u5408\u4f75\u6210\u4e00\u689d\u8a18\u9304<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u7d93\u5e38\u9700\u8981\u5c0d\u591a\u689d\u8a18\u9304\u9032\u884c\u64cd\u4f5c\uff0c\u4ee5\u4fbf\u5f9e\u4e2d\u63d0\u53d6\u6709\u7528\u7684\u4fe1\u606f\u3002\u7279\u5225\u662f\u5728MySQL\u6578\u64da\u5eab\u4e2d\uff0c\u5c07\u591a\u689d\u8a18\u9304\u7684\u55ae\u500b\u5b57\u6bb5\u5408\u4f75\u6210\u4e00\u689d\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\u3002\u9019\u7bc7\u6587\u7ae0\u5c07\u63a2\u8a0e\u5982\u4f55\u5728MySQL\u4e2d\u5be6\u73fe\u9019\u4e00\u529f\u80fd\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"%e7%82%ba%e4%bb%80%e9%ba%bc%e9%9c%80%e8%a6%81%e5%90%88%e4%bd%b5%e8%a8%98%e9%8c%84-qgAvQyLcdq\">\u70ba\u4ec0\u9ebc\u9700\u8981\u5408\u4f75\u8a18\u9304<\/h2>\n<p>\u5408\u4f75\u8a18\u9304\u7684\u9700\u6c42\u901a\u5e38\u51fa\u73fe\u5728\u4ee5\u4e0b\u5e7e\u7a2e\u60c5\u6cc1\uff1a<\/p>\n<ul>\n<li>\u6578\u64da\u5831\u544a\uff1a\u5728\u751f\u6210\u5831\u544a\u6642\uff0c\u53ef\u80fd\u9700\u8981\u5c07\u591a\u689d\u8a18\u9304\u7684\u67d0\u500b\u5b57\u6bb5\u5408\u4f75\uff0c\u4ee5\u4fbf\u66f4\u6e05\u6670\u5730\u5c55\u793a\u6578\u64da\u3002<\/li>\n<li>\u6578\u64da\u5206\u6790\uff1a\u5728\u9032\u884c\u6578\u64da\u5206\u6790\u6642\uff0c\u5408\u4f75\u8a18\u9304\u53ef\u4ee5\u5e6b\u52a9\u7c21\u5316\u6578\u64da\u96c6\uff0c\u4fbf\u65bc\u9032\u884c\u5f8c\u7e8c\u7684\u5206\u6790\u548c\u8655\u7406\u3002<\/li>\n<li>\u6578\u64da\u6e05\u7406\uff1a\u5728\u6578\u64da\u6e05\u7406\u904e\u7a0b\u4e2d\uff0c\u5408\u4f75\u91cd\u8907\u7684\u8a18\u9304\u53ef\u4ee5\u63d0\u9ad8\u6578\u64da\u7684\u6574\u9ad4\u8cea\u91cf\u3002<\/li>\n<\/ul>\n<h2 id=\"%e4%bd%bf%e7%94%a8group_concat%e5%87%bd%e6%95%b8-qgAvQyLcdq\">\u4f7f\u7528GROUP_CONCAT\u51fd\u6578<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u6700\u5e38\u7528\u4f86\u5408\u4f75\u591a\u689d\u8a18\u9304\u7684\u55ae\u500b\u5b57\u6bb5\u7684\u51fd\u6578\u662f<code>GROUP_CONCAT<\/code>\u3002\u9019\u500b\u51fd\u6578\u53ef\u4ee5\u5c07\u591a\u689d\u8a18\u9304\u7684\u503c\u5408\u4f75\u6210\u4e00\u500b\u5b57\u7b26\u4e32\uff0c\u4e26\u4e14\u53ef\u4ee5\u6307\u5b9a\u5206\u9694\u7b26\u3002<\/p>\n<h3 id=\"%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-qgAvQyLcdq\">\u57fa\u672c\u8a9e\u6cd5<\/h3>\n<pre><code>SELECT GROUP_CONCAT(column_name SEPARATOR 'separator') \nFROM table_name \nWHERE condition;<\/code><\/pre>\n<h3 id=\"%e7%a4%ba%e4%be%8b-qgAvQyLcdq\">\u793a\u4f8b<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>students<\/code>\u7684\u8868\uff0c\u8a72\u8868\u5305\u542b\u4ee5\u4e0b\u6578\u64da\uff1a<\/p>\n<pre><code>+----+-------+\n| id | name  |\n+----+-------+\n| 1  | Alice |\n| 2  | Bob   |\n| 3  | Alice |\n| 4  | Charlie|\n+----+-------+<\/code><\/pre>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u5c07\u6240\u6709\u5b78\u751f\u7684\u540d\u5b57\u5408\u4f75\u6210\u4e00\u689d\u8a18\u9304\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT GROUP_CONCAT(name SEPARATOR ', ') AS all_names \nFROM students;<\/code><\/pre>\n<p>\u57f7\u884c\u4e0a\u8ff0\u67e5\u8a62\u5f8c\uff0c\u7d50\u679c\u5c07\u6703\u662f\uff1a<\/p>\n<pre><code>+---------------------+\n| all_names           |\n+---------------------+\n| Alice, Bob, Alice, Charlie |\n+---------------------+<\/code><\/pre>\n<h2 id=\"%e4%bd%bf%e7%94%a8group-by%e9%80%b2%e8%a1%8c%e5%88%86%e7%b5%84%e5%90%88%e4%bd%b5-qgAvQyLcdq\">\u4f7f\u7528GROUP BY\u9032\u884c\u5206\u7d44\u5408\u4f75<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u80fd\u9700\u8981\u6839\u64da\u67d0\u500b\u5b57\u6bb5\u9032\u884c\u5206\u7d44\uff0c\u7136\u5f8c\u518d\u5408\u4f75\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u6839\u64da\u5b78\u751f\u7684\u540d\u5b57\u4f86\u5408\u4f75\u8a18\u9304\uff0c\u53ef\u4ee5\u9019\u6a23\u505a\uff1a<\/p>\n<pre><code>SELECT name, GROUP_CONCAT(id SEPARATOR ', ') AS student_ids \nFROM students \nGROUP BY name;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u5c07\u6703\u8fd4\u56de\u6bcf\u500b\u5b78\u751f\u7684\u540d\u5b57\u53ca\u5176\u5c0d\u61c9\u7684ID\uff1a<\/p>\n<pre><code>+---------+-----------------+\n| name    | student_ids     |\n+---------+-----------------+\n| Alice   | 1, 3            |\n| Bob     | 2               |\n| Charlie  | 4               |\n+---------+-----------------+<\/code><\/pre>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-qgAvQyLcdq\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528<code>GROUP_CONCAT<\/code>\u6642\uff0c\u6709\u5e7e\u500b\u6ce8\u610f\u4e8b\u9805\uff1a<\/p>\n<ul>\n<li>\u9ed8\u8a8d\u60c5\u6cc1\u4e0b\uff0c<code>GROUP_CONCAT<\/code>\u7684\u6700\u5927\u9577\u5ea6\u70ba1024\u5b57\u7bc0\uff0c\u53ef\u4ee5\u901a\u904e\u8a2d\u7f6e<code>group_concat_max_len<\/code>\u8b8a\u91cf\u4f86\u8abf\u6574\u3002<\/li>\n<li>\u5982\u679c\u5408\u4f75\u7684\u6578\u64da\u91cf\u904e\u5927\uff0c\u53ef\u80fd\u6703\u5c0e\u81f4\u6027\u80fd\u554f\u984c\uff0c\u56e0\u6b64\u5728\u8a2d\u8a08\u6578\u64da\u5eab\u6642\u61c9\u8003\u616e\u5230\u9019\u4e00\u9ede\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-qgAvQyLcdq\">\u7e3d\u7d50<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u4f7f\u7528<code>GROUP_CONCAT<\/code>\u51fd\u6578\u53ef\u4ee5\u65b9\u4fbf\u5730\u5c07\u591a\u689d\u8a18\u9304\u7684\u55ae\u500b\u5b57\u6bb5\u5408\u4f75\u6210\u4e00\u689d\u8a18\u9304\u3002\u9019\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u53ef\u8b80\u6027\uff0c\u9084\u80fd\u5728\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u751f\u6210\u4e2d\u767c\u63ee\u91cd\u8981\u4f5c\u7528\u3002\u7121\u8ad6\u662f\u5728\u6578\u64da\u6e05\u7406\u9084\u662f\u6578\u64da\u5831\u544a\u4e2d\uff0c\u638c\u63e1\u9019\u4e00\u6280\u8853\u90fd\u5c07\u5c0d\u6578\u64da\u5eab\u7ba1\u7406\u8005\u5927\u6709\u88e8\u76ca\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u6211\u5011\u7684<a 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