Sql去重及查询重复

[b]1、最简单的是使用distinct，去除所有查询字段信息一样的数据[/b]

---------------------------------------以下为有主键的情况下使用

2、 查询，去重，保留最小id信息

select * from people where id in (

select MIN(id) from people group by name,sex)

3、 查询全部的重复信息

select * from people where id not in (

select min(id) from people group by name,sex HAVING COUNT(*) < 2)

4、查询多余的重复信息

select * from people where id not in (

select MIN(id) from people group by name,sex)

5、删除多余重复的信息，只保留最小ID

delete from people where id not in(

select MIN(id) from people group by name,sex

)