Re: Subquery to select max(date) value

On Thu, Mar 28, 2019 at 3:59 PM Rich Shepard <rshepard(at)appl-ecosys(dot)com>
wrote:

>
> After working with this query I modified it slightly to return only the
> next_contact date:
>
> select p.person_id, p.lname, p.fname, p.direct_phone, p.active,
> o.org_name, sq.*
> from people as p
> join organizations as o on p.org_id = o.org_id
> cross join
> lateral
> (select a.next_contact
> from activities as a
> where a.person_id = p.person_id and
> p.active='True' and
> a.next_contact is not null
> order by a.next_contact DESC
> limit 1) sq;
>
> It works wellm, but the row order is not that of a.next_contact. In fact,
> there seems to be no order in the returned set. The next_contact column is
> in the lateral sub-query. Does this make a difference? I've no idea how to
> modify the query so that returned rows are in decreasing next_contact
> order.
>
> Best regards,
>
> Rich
>
> You need the ORDER BY in the outer join. (And I don't think the one
inside the lateral join is doing you any good). Try:

...
a.next_contact is not null
limit 1) sq
order by sq.next_contact DESC;

Cheers,
Ken

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