ORACLE查詢重復數據

1、查找表中多余的重復記錄，重復記錄是根據單個字段（userCode）來判斷

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

2、刪除表中多余的重復記錄，重復記錄是根據單個字段（userCode）來判斷，只留有rowid最小的記錄

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、查找表中多余的重復記錄（多個字段）

select 
    * 
from 
    user a
where 
    (a.userCode,a.userName) 
in  
    (select userCode,userName from user group by userCode,userName having count(*) > 1)

4、刪除表中多余的重復記錄（多個字段），只留有rowid最小的記錄

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、查找表中多余的重復記錄（多個字段），不包含rowid最小的記錄

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)