简单问题，用SUM函数如何去掉重复

[eliee]

一张表：
a b c
a001 b001 5
a001 b002 7
a001 b002 7
a002 b003 6
a002 b004 8
a002 b001 9

这样的表，要求a+b相同的去掉，求C列的总和
即上表应求 5+7+6+8+9 (重复去掉)
谢谢!!

[paoluo]

Select SUM(c) As c
from(Select Distinct * from TableName) A

[飞哥]

看楼上答案
路过～

[eliee]

多谢!
还有其它方法吗？因为表里不光只有三列，光靠DISTINCT * 没办法去掉重复值
即：
a b c d e
a001 b001 5 as zz1
a001 b002 7 df zz2
a001 b002 7 dc zz3
a002 b003 6 vre zz4
a002 b004 8 ed zz2
a002 b001 9 ww zz7
多谢了!!

[yangys]

select a,b,sum(c) from tb group by a,b

[paoluo]

Select SUM(c) As c
from(Select Distinct a,b,c from TableName) A

舉例最好能舉出能代表你的需求的例子，以免寫出不合適的語句。

[paoluo]

yangys(杨杨) ( ) 信誉：100 2006-05-06 14:23:00 得分: 0



select a,b,sum(c) from tb group by a,b


------------------------------------------
沒看清要求。

[$扫地僧$]

那你就只要你那3列吗!

Select SUM(c) As c
from(Select Distinct a,b,c from TableName) A

[yangys]

理解错误
这样也可以啊

select sum(a.c) from (
select a,b,min(c)as c from tb group by a,b)a

[eliee]

不好意思!不好意思!举例不好!
如果 是：
a b c d e
a001 b001 5 as zz1
a001 b002 7 df zz2
a001 b002 7 dc zz3
a002 b003 6 vre zz4
a002 b004 5 ed zz2
a002 b001 7 ww zz7
这样的话呢？

[paoluo]

如果是這樣，

Select SUM(c) As c
from(Select Distinct a,b,c from TableName) A

這個應該可以啊。

[eliee]

可是我只是想把a+b重复的去掉，只取一条，就是要：
5+7+6+5+7的值，而把
a001 b002 7 dc zz3
这条记录省去了!

[eliee]

啊，对了!是可以的!对的!谢谢了!
如果是这样：
a b c d e
a001 b001 5 as zz1
a001 b002 7 df zz2
a001 b002 9 dc zz3
a002 b003 6 vre zz4
a002 b004 5 ed zz2
a002 b001 7 ww zz7
怎样实现呢!!

[paoluo]

那就要看你怎麼取了。

相同的a、b，c取最大的還是最小的。

取最大的
Select SUM(c) As c from(Select a,b,Max(c) As c from TableName Group By a,b) A

取最小的
Select SUM(c) As c from(Select a,b,Min(c) As c from TableName Group By a,b) A

[eliee]

ok!谢谢各位了!
给分!