转载---MYSQL查询重复记录的方法

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)