Re: Extract only maximum date from column

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