现有一张表table字段
a b
1 a
2 a
1 b
4 b
5 b 1 c
2 c
6 c 1 d
2 d
2 d
如果我想以b分组,其中a字段中只包含1,2的值,而且只能包含1,2不能有别的纪录。譬如上边我
得到的是
a b
1 a
2 a 1 d
2 d
2 d
这个怎么查啊,请教各位大侠了,小弟刚出家不久,现在工作碰到。谢谢了
在线等啊!
a b
1 a
2 a
1 b
4 b
5 b 1 c
2 c
6 c 1 d
2 d
2 d
如果我想以b分组,其中a字段中只包含1,2的值,而且只能包含1,2不能有别的纪录。譬如上边我
得到的是
a b
1 a
2 a 1 d
2 d
2 d
这个怎么查啊,请教各位大侠了,小弟刚出家不久,现在工作碰到。谢谢了
在线等啊!
from (
select 1 a, 'a' b from dual
union all
select 2 a, 'a' b from dual
union all
select 1 a, 'b' b from dual
union all
select 4 a, 'b' b from dual
union all
select 5 a, 'b' b from dual
union all
select 1 a, 'c' b from dual
union all
select 2 a, 'c' b from dual
union all
select 6 a, 'c' b from dual
union all
select 1 a, 'd' b from dual
union all
select 2 a, 'd' b from dual
union all
select 2 a, 'd' b from dual) T
where T.a in (1,2)
select a,b
from table
where a=1 or a=2
group by a,b
select a,b from yourtable where a=1 or a=2 group by b,a
select *
from tablename t1
where not exists
(
select t2.b
from tablename t2
where t2.a not in (1,2)
and t1.b = t2.b
);
A B
---------- -
1 a
2 a
1 d
2 d
2 d