On Thursday, December 4, 2025, Rich Shepard <
rshepard@appl-ecosys.com> wrote:
I want the script to extract only the maximum `next_contact' date and
haven't learned how to do this from my reading of web sites.
The script:
select p.person_nbr, p.company_nbr, c.next_contact
from people as p, contacts as c
where c.next_contact >= '2025-11-01'
group by p.person_nbr, p.company_nbr, c.next_contact
order by p.person_nbr, p.company_nbr, max(c.next_contact);
returns all contacts rather than only the latest one.
Is using a sub-select the proper way?
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.
You also seem to have completely missed joining people to contracts - suggest using explicit “join” clauses to make that error less likely.
David J.
