MYSQL查询重复记录的方法

select * from hengtu_demandpush a
where (a.did,a.mid) in (select did,mid from hengtu_demandpush group by did,mid having count(*) > 1)

或

select * from hengtu_demandpush group by did,mid having count(*)>1

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

1. select * from people   
2. 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

1. delete from people   
2. where peopleId in (select peopleId from people group by peopleId   having count(peopleId) > 1)   
3. 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）

1. select * from vitae a   
2. 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

1. delete from vitae a   
2. where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)   
3. 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

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

MYSQL查询重复记录的方法

原文：http://www.cnblogs.com/luojianqun/p/4635184.html