求一条SQL语句

[yyoinge]

有两个表 t_A 与 t_B
表t_A如下：
----------------------------------
Ca Da
----------------------------------
A 1
B 2
C 3

表t_B如下：
----------------------------------
Cb Db
----------------------------------
B 2
C 3
D 4

要生成如下数据，用一条语句怎么写
----------------------------------
Cc Dc
----------------------------------
A 1
B 4
C 6
D 4

怎么写？

[zheninchangjiang]

select ca,sum(cb) from
(select ca,cb from tb_a
union all
select * from tb_b)

[AcHerat]

select ca,sum(da)da
from (
    select ca,da from t_A
    union all
    select ca,da from t_B
)t
group by ca

[yyoinge]

就是存在相同的累加， 不同的分别列出来
Ca与Cb列中的数据都是唯一的

[让你望见影子的墙]

select ca,sum(cb) from
(select ca,cb from tb_a
union all
select * from tb_b)K
group by ca

[yyoinge]

只能用UNION 吗？

[bancxc]

select CC,Sum(Dc) DC from
(select Ca CC,Da DC from t_A union all
select Cb,Db from  t_B B ) C Group by CC

[jwdream2008]

select Ca as Cc,Da as CC from t_A
union
select Cb as Cc,Db as CC from t_B

[yyoinge]

select ca,sum(da)da
from (
    select ca,da from t_A
    union all
    select ca,da from t_B
)t
group by ca

以外的还有吗？不用sum，不用union

[让你望见影子的墙]

[Quote=引用 9 楼 yyoinge 的回复:]
SQL code
select ca,sum(da)da
from (
select ca,da from t_A
union all
select ca,da from t_B
)t
group by ca



以外的还有吗？不用sum，不用union
[/Quote]

有，但是都比较麻烦。这个是最简单的，最有效的

[bala7229291]

应该还能full join楼主你尝试一下