Re: Selecting table row with latest date [RESOLVED]

On Thu, Aug 19, 2021 at 2:52 PM Rich Shepard <rshepard(at)appl-ecosys(dot)com>
wrote:

> On Thu, 19 Aug 2021, David G. Johnston wrote:
>
> > I thought you said (p.person_nbr, c.contact_date) is already unique?
>
> Yes, that's the PK for the contacts table. I'm still unsure what needs to
> be
> explicitly included in a query. Quite often I leave out a column and
> postgres tells me it needs to be included in order by or group by.
>
>
Well, in this case I suspect you had made a different mistake which caused
the error message (probably the max(c.next_contact)) but instead of solving
the original problem (removing the max(...)) you decided that two wrongs
(adding or extending a group by) would hopefully make a right (which it
did, technically). But while the query works it is definitely not
conceptually correct.

David J.