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MySQL查询数据库中重复的记录几条sql
时间:2015-09-24 编辑:简简单单 来源:一聚教程网
1.根据表中单个字段(name)来查询重复记录
SELECT * FROM user WHERE name IN ( SELECT name FROM user GROUP BY name HAVING COUNT(name) > 1 );
2.根据表中单个字段(name),删除重复记录,只保留id最小的记录
DELETE FROM user WHERE name IN ( SELECT name FROM user GROUP BY name HAVING COUNT(name) > 1 ) AND id NOT IN (SELECT min(id) FROM user GROUP BY name HAVING COUNT(name) > 1);
3.根据表中多个字段(name, age)来查询重复记录
SELECT * FROM user u WHERE (u.name, u.age) IN ( SELECT name, age FROM user GROUP BY name, age HAVING COUNT(*) > 1 );
4.根据表中多个字段(name, age),删除重复记录,只保留id最小的记录
DELETE FROM user u WHERE (u.name, u.age) IN ( SELECT name, age FROM user GROUP BY name, age HAVING COUNT(*) > 1 ) AND id NOT IN (SELECT min(id) FROM user GROUP BY name, age HAVING COUNT(*) > 1);
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