oracle刪除一個表內的重復數據，

查詢以及刪除一個數據庫表內的重復數據。

1.查詢表中的多余的重復記錄，重復記錄是根據單個字段來判斷的。

select * from biao where id in (select id from biao group by id having count(id) >1 )

2.刪除表中的多余的重復記錄，重復記錄是根據（id）來判斷，只留rowid 最小值。

 delete from  biao where id  in   ( select  id from biao group by id having count(id) )  and  rowid not in  ( select  min(rowid) from  biao group by id having count(id)>1 )

delete from xuesheng
where T_NAME in
(select T_NAME
from xuesheng
group by T_NAME, T_ADDRESS, T_PHONE, T_BIRTHDAY
having count(*) > 1) --重復數據
and rowid not in
(select max（rowid）
from xuesheng
group by T_NAME, T_ADDRESS, T_PHONE, T_BIRTHDAY
having count(*) > 1) --保留一條重復數據

 

3.刪除表中重復的記錄（多個字段），

delete from xuesheng
where T_NAME in
(select T_NAME
from xuesheng
group by T_NAME, T_ADDRESS, T_PHONE, T_BIRTHDAY
having count(*) > 1) --不保留重復數據

 

 

 

 

 

 

 

 

 

來自：https://www.cnblogs.com/252e/archive/2012/09/13/2682817.html