Sql去重及查詢重復

1、最簡單的是使用distinct，去除所有查詢字段信息一樣的數據

    

---------------------------------------以下為有主鍵的情況下使用

2、 查詢，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、 查詢全部的重復信息
select * from people where id not in (

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

 

4、查詢多余的重復信息
select * from people where id not in (

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

 

5、刪除多余重復的信息，只保留最小ID
delete from people where id not in(
    select MIN(id) from people group by name,sex
)