On 12/4/25 1:39 PM, Rich Shepard wrote:
> On Thu, 4 Dec 2025, David G. Johnston wrote:
>
>> I would go with a lateral join subquery of the contracts table. Using an
>> aggregates to perform ranking is an anti-pattern. You want the contract
>> ranked first when ordered by contract_date. Either use a window function
>> to explicitly rank the contracts or use a limit/fetch clause to simply
>> return the first ordered one.
>
> David,
>
> I'm closer, but still missing the proper syntax:
>
> select p.person_nbr, p.company_nbr, c.next_contact
> from people as p, contacts as c
> join lateral (select max(c.next_contact) as last_contact
> where p.person_nbr = c.person_nbr and
> last_contact >= '2025-11-01'
> )
> c on true;
>
> resulting in:
> psql:companies-contacted-2025.sql:9: ERROR: aggregate functions are not
> allowed in FROM clause of their own query level
> LINE 3: join lateral (select max(c.next_contact) as last_contact
Would the below work?:
WITH lc AS (SELECT person_nbr, max(next_contact) AS last_contact from
contacts where next_contact > '2025-11-01' group by c.person_nbr)
select p.person_nbr, p.company_nbr, lc.last_contact from people AS p
join lc on p.person.nbr = lc.person_nbr;
>
> Regards,
>
> Rich
>
>
--
Adrian Klaver
adrian.klaver@aklaver.com
