MySQL查询重复数据
发布时间:2020-12-12 02:21:22 所属栏目:MySql教程 来源:网络整理
导读:? 假设有一个用户表 user,数据如下: 1、查询表中 uid 重复的数据 SELECT id,uid,name FROM USER WHERE uid IN ( uid USER GROUP BY uid HAVING COUNT (uid) 1 ); 2、查询表中重复数据,排除最小id user user 1 ) AND id NOT SELECT MIN (id) 1 ); 3、删除
? 假设有一个用户表 user,数据如下: 1、查询表中 uid 重复的数据SELECT id,uid,name FROM USER WHERE uid IN ( uid USER GROUP BY uid HAVING COUNT(uid) > 1); 2、查询表中重复数据,排除最小iduser user 1) AND id NOT SELECT MIN(id) 1); 3、删除表中重复数据,如果是重复数据,则保留id最小的一条DELETE WHERE id u.id FROM ( id USER uid USER uid ) SELECT (id) 1)) AS u); 4、遇到的问题:一开始直接使用以下语句删除,报错:You can’t specify target table ‘user’ for update in FROM clause ? id USER uid uid ) SELECT (id) 1)); ? 查资料后得知: ? AS u);
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