日期:2014-05-16  浏览次数:20706 次

MYSQL查询重复记录的方法[转载]

MYSQL查询重复记录的方法很多,下面就为您介绍几种最常用的MYSQL查询重复记录的方法,希望对您学习MYSQL查询重复记录方面能有所帮助。

1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断

?

select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)  
?

?

2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录

?

delete from people where peopleId in (select peopleId from people group by peopleId   having count(peopleId) > 1)  and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)   
?

3、查找表中多余的重复记录(多个字段)

?

select * from vitae a  where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
?

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

?

delete from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)  and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)    
?

5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录

?

select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)  and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)   

?

?

转载:http://database.51cto.com/art/201011/235159.htm

?