Re: Extract only maximum date from column

From: Bryan Sayer <blslists(at)gmail(dot)com>
To: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: Extract only maximum date from column
Date: 2025-12-04 20:01:46
Message-ID: d0606565-1fad-419d-922c-b3e8f76495a6@gmail.com
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I believe in general you need

having c.next_contact = max(c.next_contact)

(at least in ANSI SQL) Use having for after the join has occured

*Bryan Sayer*
Retired Demographer/Statistician
/In a world in which you can be anything, *be kind*/
On 12/4/2025 2:55 PM, Rich Shepard 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?
>
> TIA,
>
> Rich
>
>

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