sql如何筛选出重复数据

在电脑上打开数据库，这里新建一张含有重复数据的user表做示例。

查询出了数据库中user表的重复数据。

select * from user where name in (select name from user group by name having count(name) > 1)

删除姓名重复的数据

delete from user where   name in (select name from user group by name  having count(name) > 1)

去掉重复数据，这里去掉了张三的重复数据

select distinct name from user

去掉班级相同的重复数据

select distinct class from user

去掉两个字段的重复数据

select distinct name,class from user