Re: DONT_CARE Aggregate - Mailing list pgsql-general

From Marti Raudsepp
Subject Re: DONT_CARE Aggregate
Date
Msg-id CABRT9RDhjKr4+PmMj+vwCh51oXWaf2axR9U8GO3uQpp31QehbA@mail.gmail.com
Whole thread Raw
In response to DONT_CARE Aggregate  (Robert James <srobertjames@gmail.com>)
Responses Re: DONT_CARE Aggregate  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Thu, Dec 20, 2012 at 3:28 AM, Robert James <srobertjames@gmail.com> wrote:
> Is there an aggregate that will return an arbitrary instance? That is,
> not necessarily the max or min, just any one? (Which might perform
> better than max or min)
>
> More importantly:
> Is there one which will return an arbitrary instance as long as it's not NULL

There's an extension on PGXN which implements first()/last()
aggregates in C: http://pgxn.org/dist/first_last_agg/

It should be slightly faster than min()/max(), but the difference is
probably not significant in more complex queries.

Regards,
Marti


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