Am 01.10.2017 um 14:41 schrieb Mariel Cherkassky:
Hi,
I need to use the max function in my query. I had very bad performance
when I used the max :
SELECT Ma.User_Id,
COUNT(*) COUNT
FROM Manuim Ma
WHERE Ma.Bb_Open_Date =
(SELECT max(Bb_Open_Date)
FROM Manuim Man
WHERE Man.User_Id = Ma.User_Id
)
GROUP BY Ma.User_Id
HAVING COUNT(*) > 1;
Any idea how can I continue from here ? Thanks , Mariel.
Maybe you can rewrite it, for instance to
select distinct on (user_id, bb_open_date) user_id, bb_open_date,
count(1) from Manuim group by 1,2 having count(1) > 1;
maybe much cheaper, but untested! If not, please share more details, at
least table-definition.
Regards, Andreas
--
2ndQuadrant - The PostgreSQL Support Company.
www.2ndQuadrant.com
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
