Which group by function to use in following case?

Question

Table name: PVH
| Processid | Name | Timechanged | Value |
| 268436769 | filecount | 10/1/2008 2:59:01.006000 AM | 0 |
| 268436769 | filecount | 10/1/2008 2:45:33.004000 AM | 100 |
I want "value" where max(timechanged) and groupby appianprocessid and name …… that is "0"
How to get that using simple SQL? I tried following two approaces….
Select max(timechanged), value from pvh where appianprocessid=268436769 group by appianprocessid, name, value
This query returns me two values...
Select max(timechanged), max(value) from pvh where appianprocessid=268436769 group by appianprocessid, name
This
Thanks
Sandeep

Answer 1

Hello,
Try:
SELECT name,  value, timechanged
  FROM PVH p1
WHERE timechanged = (
  SELECT MAX(timechanged)
    FROM PVH p2
  WHERE p1.appianprocessid = p2.appianprocessid)
WHERE appianprocessid = 268436769 ;Edited by: SeánMacGC on Jul 14, 2009 2:55 PM
And another way:
SELECT name, value, timchanged
  FROM (
  SELECT name,  value, timechanged,
        ROW_NUMBER() OVER (PARTITION BY appianprocessid ORDER BY timechanged DESC) row_num
    FROM PVH)
WHERE appianprocessid = 268436769
    AND row_num <= 1;And if the timechanged can have duplicate values for each appianprocessid, and you want all rows with the same MAX(appianprocessid), change ROW_NUMBER to RANK in that second query.