Re: select with max functions

Andreas I tried to rewrite it with the function rank() but I failed. The
query you wrote isnt the same as what I search. Moreover, I cant use
explain analyze because it is taking to much time to run and I'm getting
timeout..

2017-10-01 21:48 GMT+03:00 Andreas Kretschmer <andreas(at)a-kretschmer(dot)de>:

>
>
> 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(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-performance
>