ORACLE查询重复数据

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

select 
	* 
from 
	user
where 
	userCode
in 
	(select  userCode  from  user group by  userCode having count (userCode) > 1)

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

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

3、查找表中多余的重复记录（多个字段）

select 
	* 
from 
	user a
where 
	(a.userCode,a.userName) 
in  
	(select userCode,userName from user group by userCode,userName 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 
	user a
where
	(a.userCode,a.userName) 
in   
	(select userCode,userName from user group by userCode,userName having count(*) > 1)
and rowid not in 
	(select min(rowid) from user group by userCode,userName 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 
	user a
where 
	(a.userCode,a.userName)  
in   
	(select userCode,userName from user group by userCode,userName having count(*) > 1)
and rowid not in 
	(select min(rowid) from user group by userCode,userName having count(*)>1)