sql语句，sum相关。比较难~~求教~~~

[zhyoli]

如何对A表里的A1列和A2列相乘得到的值进行SUM统计。
比如：
A1 A2
---------------
10 20.2
22.4 33.9


先计算A1*A2的值。然后sum这个值放入一个标量。

[boblaile]

帮你顶下
不会！
好像要用到表的内连接

[huailairen]

create table MM(A1 float, A2 float)
---------------
insert into MM values(10 , 20.2)
insert into MM values(22.4 , 33.9)

declare @m float
set @m=0
select @m=@M+A1*A2 from MM

print @M

[zhyoli]

最好是可以AS到某个变量。这样便于我输入到屏幕上。而且定义变量没有办法的。我是一条查询语句。。没有办法定义的。

[boblaile]

我的表aa 有字段
a,b,c求a*b然后sum求和
SELECT sum(DISTINCT p.a*k.b) as g
FROM aa AS p INNER JOIN aa AS k
ON p.c = k.c

[xeqtr1982]

declare @t table(a1 dec(10,2),a2 dec(10,2))
insert into @t select 10,20.2
union all select 22.4,33.9

select sum(a1*a2) as [sum] from @t
--这样？

[aniude]

---------------------
select sum_all=sum(a1*a2) from a

[zhyoli]

我的查询语句牵涉到多个表。。不过只有一个表里需求运算。。。我用sum(A1*A2) as xxx 提示什么group by，还有having 一类的。我没有用group by 啊。。
是不是要在where 或者order by 语句后面写点什么~

[aniude]

declare @t table(a1 float,a2 float)
insert into @t select 10,20.2
union all select 22.4,33.9
select sum_all = sum(a1*a2) from @t
declare @tt float

sum_all
-----------------------------------------------------
961.3599999999999

[zhyoli]

我的数据库是 db2的。。。。。=号不认识啊~

[boblaile]

db2的怎么到sql来了

[zhyoli]

但是我的 客户端用的.net啊 ～sql应该相同的吧····

[wuyg719]

select sum(a3) from(select A1*A2 a3 from mytable)

[zfl2k]

sql server oracle 可以直接：
select sum(a1*a2) as a3 from table [where] [group]

[zfl2k]

如果要显示其他列的话就必须在group by 里出现该字段:
select c1,c2,sum(a1*a2) as a3 from table [where] [group by c1,c2]

[DigData]

sum 是aggregate函数，和其它列一起使用时要加group分组的.　如

select c1,c2,sum(c1*c2) as res from tab group by 1,2

[zhaiyf]

目的只是求和的话select sum(a3) from(select A1*A2 a3 from mytable)可以实现。`

[zlp321002]

--SQL server 2005
declare @t float;
WITH TBCTE
AS
(
SELECT A1*A2 as sumA1A2 FROM TB
)
SELECT @t=sum(sumA1A2) FROM TBCTE
select @t
/*
----------------------
961.36

(1 行受影响)
*/