Query to find Last updated..

Question

Hi all,
If I have a table with accounts, users and last_on_date, how can I find the user who accessed an account most recently.
Say, the table is as follows:
a/c user c_date
a1 u1 03/04/2007
a1 u2 03/05/2007
a2 u3 03/05/2007
a2 u1 03/07/2007
a2 u2 03/06/2007
a3 u3 04/05/2007
What query would fetch the following:
a/c user c_date
a1 u2 03/05/2007
a2 u1 03/07/2007
a3 u3 04/05/2007
Any help is appreciated.

Answer 1

That's only part of the OP's Q.
The OP asked for the most recent user of a particular account not the most recent access of each user to each account.
so this would do the trick:
SELECT AC,
       USER,
       C_DATE
FROM (SELECT AC,
             USER,
             C_DATE,
             ROW_NUMBER() OVER (PARTITION BY AC ORDER BY C_DATE DESC) RN
        FROM YOUR_TABLE)
WHERE RN = 1;