oracle刪除重復數據只保留一條

-- 如表role_user的數據

ROLEID       USERID
  15       88010000000074    
  15       88010000000074    
  15       88010000000074    

-- 刪除相同記錄只剩下一條記錄

 

根據兩個字段查詢重復數據 (roleid，userid)

select * from role_user a where (a.roleid,a.userid) in(select roleid,userid from role_user group by roleid,userid having count(*) > 1)

刪除重復數據只保留一條

delete from role_user where rowid not in (select min(rowid) from role_user group by roleid , userid )

 

下面的只根據userid進行查詢與刪除

select count(1),USERID from role_user group by USERID HAVING count(1)>1 

DELETE from role_user WHERE (userid) IN ( SELECT userid FROM role_user GROUP BY userid HAVING COUNT(userid) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM role_user GROUP BY userid HAVING COUNT(*) > 1);