删除表中重复数据

oracle查询重复数据并删除，只保留一条记录
 
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 byId 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)
 
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 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)