Re: picking max from list

On Wed, Dec 10, 2003 at 15:37:10 -0500,
Jodi Kanter <jkanter(at)virginia(dot)edu> wrote:
> I have a query that produces results similar to this:
>
> run# rd_pk group#
> 0 9209 5
> 1 9209 8
> 0 9520 2
> 1 9520 5
> 0 9520 etc....
> 0 8652
> 1 8652
> 2 8652
> 0 8895
> 1 8894
>
> Ultimately I want to know the group number for EACH rd_pk with the
> highest run number. Can this be done in one query? Or will I need to
> code with a loop?
> Thanks

You can do this using the postgres distinct on extension.
The query would look something like:
select distinct on (rd_pk) run, rd_pk, group from table_name
order by run desc;