Question

I can’t seem to understand why, but i’m trying this query :

SELECT called,caller,time,duration
FROM Calls
GROUP BY called,caller,time,duration

But that returns rows with same called value which is not i want.

Basically i’m trying to build a bigger query, just going step by step with that.
i need a query to return latest entry for every called per caller

Answer 1

Assuming that you want only distinct called values but all columns. If there are multiple called i take only the last (ordered by time):

WITH CTE AS
(
   SELECT called,caller,time,duration,
      RN = ROW_NUMBER() OVER (PARTITION BY called ORDER BY time DESC)
   FROM Calls
)
SELECT called,caller,time,duration
FROM CTE WHERE RN = 1