Date: Thu, 4 Dec 2025 12:22:31 -0800 (PST)
From: Rich Shepard <rshepard@appl-ecosys.com>
To: "pgsql-general@postgresql.org" <pgsql-general@postgresql.org>
Subject: Re: Extract only maximum date from column
In-Reply-To: <CAKFQuwZEWkgQeWSB7nqzBjHS8kP7kvouT6jhKvfe_G2e3cJvOQ@mail.gmail.com>
Message-ID: <71e7ffd-2151-cf3c-b1d9-5b8d66bb9b6@appl-ecosys.com>
References: <db81f086-e1a5-5798-f9bd-5bed5b1bc7f4@appl-ecosys.com> <CAKFQuwZEWkgQeWSB7nqzBjHS8kP7kvouT6jhKvfe_G2e3cJvOQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8BIT
Archived-At: <https://www.postgresql.org/message-id/71e7ffd-2151-cf3c-b1d9-5b8d66bb9b6%40appl-ecosys.com>
Precedence: bulk

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,

It's 'contacts' rather than 'contracts'; a minor typo.

I'll read on making a lateral join. Thanks.

> You also seem to have completely missed joining people to contracts -
> suggest using explicit “join” clauses to make that error less likely.

Oops! My bad. Fixed.

Regards,

Rich