Question : combe SQL query

Hi,

I have data looks like this, I need to find out d12, and d34, in this case, which will be 25 and 40, since in d12, two have same date. for d34, 8/1 abd 7/1 have the same date, so it would be 40. I could use a query for each number, my queston is, is there a way to combine into one query and return two numbers. Basically, I want to hit db once instead of twice...thx

d1 d2 d3 d4 d12 d34
10/1/2009 9/1/2009 9/5/2009 5
9/1/2009 7/5/2009 8/1/2009 25
8/1/2009 7/10/2009 8/15/2009 35
7/1/2009 7/5/2009 8/1/2009 7/10/2009 8/15/2009 25 35

Code Snippet:

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select distinct d1,d2, sum(d12)
from mytable


select distinct d3,d4, sum(d34)
from mytable

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Answer : combe SQL query

Since you use different criteria for "uniqueness" for d12 and d34, you need two selects, but you can combine them e.g. by using a UNION. I would do like this:

select d1, d2, sum(d12), null, null, null from mytable group by d1, d2
union all
select null, null, null, d3, d4, sum(d34) from mytable group by d3, d4