not exists无效？
select * from testa

select * from testb


select * from testa
where not exists
(select * from testb)

结果为空，为什么,该怎么取出差异行

exists oracle
[解决办法]
这个结果必须为空啊....
选择差异行：
select * from testa a
where not exists
(select * from testb b where a.H0=b.H0)
[解决办法]
最简单的方法就是利用minus
select * from testa
minus
select * from testb