求一SQL语句

[ykwang]

语句如下：
select dh,Savedata as a1,'' as a2 from savetable where savename='A'
union all
select dh,'' as A1,Savedata as a2 from savetable where savename='B'

假设得到的返回结果为：

DH a1 a2
001 A-500 空格 注：第一条语句返回 每个DH只会有一条记录
001 空格 B-300 注：第二条语句返回 每个DH只会有一条记录

我想实现的结果为

DH A1 A2
001 A-500 B-300

如何使单号相同，数据自动摆在一起。

[唐诗三百首]

select dh,sum(a1) 'A1',sum(a2) 'A2'
from
(select dh,Savedata as a1,0 as a2 from savetable where savename='A'
union all
select dh,0 as A1,Savedata as a2 from savetable where savename='B'
) t
group by dh

[ykwang]

问题是 这个不是数值呢。 不能使用 sum

[中国风]

select dh,max(case when savename = 'A'  then Savedata end) as a1,
max(case when savename = 'B'  then Savedata end) as a2 
from savetable 
where savename in('A','B') 
group by dh

[中国风]

直接用case when +Max

楼主语句改为

select dh,max(a1) as a1,max(a2) as a2
from (select dh,Savedata as a1,'' as a2 from savetable where savename='A'
union all
select dh,'' as A1,Savedata as a2 from savetable where savename='B')t
group by dh

[rmini]

需求真是多样化啊，收藏了