Question

My database table is something like this:

#tblMain
ID     Value  CreatedDate
________________________________________
1      25     2011-10-11 14:00:45.910
1      20     2011-10-26 14:00:12.910
2      27     2011-10-14 14:00:32.910
2      39     2011-10-14 14:00:28.910
2      54     2011-10-17 14:00:27.910
3      67     2011-10-25 14:00:16.910
3      79     2011-10-25 14:00:02.910
4      34     2011-10-26 14:00:14.910
4      24     2011-10-26 14:00:06.910
4      88     2011-10-26 14:00:47.910
5      12     2011-10-26 14:03:14.910
5      34     2011-10-26 14:04:06.910
5      55     2011-10-26 14:04:47.910

I’ll get a list of IDs from a different table. So now I want to join the above table to this table based on ID, in such a way that I’ll get 1 row for every distinct ID with a value field from the row with MIN(CreatedDate) i.e. oldest value for that particular ID. i.e. for every row, the selected row would be :

SELECT TOP(1) * from #tblMain ORDER BY CreatedDate ASC where ID = 1

SELECT TOP(1) * from #tblMain ORDER BY CreatedDate ASC where ID = 2...and so on.

Thus, my output should be like this:

ID  Value  CreatedDate               X   Y   Z(other columns from other tables)
_______________________________________________________________________________
1   25     2011-10-11 14:00:45.910
2   39     2011-10-14 14:00:28.910
3   79     2011-10-25 14:00:02.910
4   24     2011-10-26 14:00:06.910
5   12     2011-10-26 14:03:14.910

Trust me, I’ve tried my best to present my requirements as clearly as I possibly can, still if there’s something unclear, let me know. Expecting a quick response. Thanks.

Answer 1

Try:

select m.ID, m.Value, m.CreatedDate, o.x, o.y, o.z
from (select tM.*, row_number() over (partition by ID order by CreatedDate) rn
      from #tblMain tM) m
left join otherTable o on m.ID = o.ID
where m.rn=1