Oracle删除重复数据

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.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)

3.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)

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)