oracle---删除重复数据

Oracle 删除重复数据只留一条

 

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 id,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 Id,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)