[Oracle] 如何删除重复数据

查询及删除重复记录的SQL语句

 

1、查找表中多余的重复记录，重复记录根据单个字段（Id）来判断

 

select * from table where Id in (select Id from table group by Id having count(Id) > 1)

 

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

 

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

 

3、查找表中多余的重复记录（多个字段）

 

select * from table a where (a.Id,a.seq) in(select Id,seq from table group by Id,seq having count(*) > 1)

 

4、删除表中多余的重复记录（多个字段），只留rowid最小的记录

 

delete from table a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from table group by Id,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 table a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from table group by Id,seq having count(*)>1)

原文链接： http://www.cnblogs.com/252e/archive/2012/09/13/2682817.html