DB2中查询有重复记录的数据
如筛选出来一个字段中的重复记录
如表a
id username password
1 1 1
2 1 1
3 2 2
4 2[ 4
如何将username中有重复的记录全部筛选出来，新手求指导。
[解决办法]

select * from 表a where username in (
  select username from 表a
  group by username
  having count(*) > 1
)

[解决办法]
select * from 如表a t where exists (select 1 from 如表a where username=t.username and id!=t.id)