Re: retrieving primary key for row with MIN function

On Wed, Apr 29, 2009 at 6:30 AM, Marcin Krol <mrkafk(at)gmail(dot)com> wrote:
> Hello everyone,
>
> I need to retrieve PK (r.id in the query) for row with MIN(r.start_date),
> but with a twist: I need to select only one record, the one with minimum
> date.
>
> Doing it like this does not solve the problem:
>
> SELECT h.id AS host_id, MIN(r.start_date) AS reservation_start_date, r.id AS
> reservation_id
> FROM hosts h
> LEFT OUTER JOIN reservation_hosts rh ON rh.host_id = h.id
> LEFT OUTER JOIN reservation r ON r.id = rh.reservation_id AND (r.start_date,
> r.end_date) OVERLAPS ('2009-04-29'::date, '2010-04-29'::date)
> GROUP BY h.id, r.id
> ORDER BY reservation_start_date ASC
>

Couldn't you just use something like

select r.id from (join tables here) order by date asc limit 1

or something like that?