oracle数据库根据字段删除重复数据的方法

转载自原文https://www.cnblogs.com/zfox2017/p/7676237.html

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，重复记录是根据单个字段（Id）来判断

 

select * from 表 where Id in (select Id from 表 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 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);

 

3、查找表中多余的重复记录（多个字段）

 

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

 

4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录

 

delete from 表 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 表 group by Id,seq having count(*)>1)