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:

1: 2: 3: 4: 5: 6:

select distinct d1,d2, sum(d12) from mytable select distinct d3,d4, sum(d34) from mytable

Open in New Window

Select All

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