Question

I have the following table

RecordID     Group     Date        Value
----------------------------------------
 1           Test 1   1/01/2012     10
 2           Test 1   1/01/2012     10
 3           Test 1   1/01/2012     20
 4           Test 2   1/01/2012     20
 5           Test 1   2/01/2012     10
 6           Test 2   2/01/2012     30
 7           Test 1   2/01/2012     20
 8           Test 1   2/01/2012     20
 9           Test 2   2/01/2012     20
10           Test 1   3/01/2012     10
11           Test 2   3/01/2012     10
12           Test 2   3/01/2012     20
13           Test 3   3/01/2012     10
14           Test 1   4/01/2012     10

I need to get all RecordIds, where for the same date and same group it has the lowest value and disregard all records for the same date and group that have greater value. So my query needs to group by “date” and “group” and find records with lowest value, that is result should be:

RecordIds: 1, 2, 4, 5, 9, 10, 11, 13, 14

Answer 1

You can use rank in a sub query.

select T.RecordID,
       T.[Group],
       T.Date,
       T.Value
from 
  (
    select RecordID,
           [Group],
           Date,
           Value,
           rank() over(partition by [Group], Date order by Value) as rn
    from YourTable
  ) as T
where T.rn = 1
order by T.RecordID

SQL Fiddle