On Mon, 17 May 2004, Stijn Vanroye wrote:
> Are you sure about that Edmund?
>
> I have the following query:
> select distinct on (task_id, date) task_id, workhour_id, date from
> (
> select task_id, workhour_id, begindate as date from workhour
> UNION
> select task_id, workhour_id, enddate as date from workhour
> )as dist1
This gets you first rows distincted by task_id, workhour_id and date
and then only rows distincted by task_id and date (and an unpredictable
workhour_id).
> if I use the query without the top level select, like this:
> select task_id, workhour_id, begindate as date from workhour
> UNION
> select task_id, workhour_id, enddate as date from workhour
This gets rows distincted by task_id, workhour_id and date.