日期:2014-05-17 浏览次数:20964 次
select distinct t.a,t.b
from 
(select '1' as a,'A' as b from dual
union all
select '1','A'  from dual
union all
select '2','B' from dual
union all
select '2','B' from dual )t
--------------------------------
       A    B
1    1    A
2    2    B