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From: David G. Johnston <[email protected]>
To: Rich Shepard <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: Extract only maximum date from column
Date: Thu, 4 Dec 2025 15:29:04 -0700
Message-ID: <CAKFQuwaTe2vX30erug=2v0G5BL3G=vYvwNC-8jJFkKUe3EimEQ@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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	<[email protected]>

On Thursday, December 4, 2025, Rich Shepard <[email protected]>
wrote:

> On Thu, 4 Dec 2025, David G. Johnston wrote:
>
> As mentioned, the aggregate max should be avoided - you aren’t doing
>> statistics, you are ranking.
>>
>
> David,
>
> Got it.
>
> Select person.*, lastcontact.* from person join lateral (select contact.*
>> from contact where contact.person_id=person.person_id order by
>> last_contact_date desc limit 1) as lastcontact on true;
>>
>
> Select person.*, lastcontact.*
> from people
> join lateral (select contact.*
>      from contacts
>      where contacts.person_nbr = people.person_nbr
>      order by last_contact_date
>      desc limit 1)
> as lastcontact on true;
>
> psql:companies-contacted-2025.sql:10: ERROR:  missing FROM-clause entry
> for table "contact"
> LINE 3: join lateral (select contact.*
>
> So:
> Select person.*, lastcontact.*
> from people
> join lateral (select contacts.*
>      from contacts
>      where contacts.person_nbr = people.person_nbr
>      order by last_contact_date
>      desc limit 1)
> as lastcontact on true;
>
> psql:companies-contacted-2025.sql:10: ERROR:  column "last_contact_date"
> does not exist
> LINE 6:      order by last_contact_date
>
>

I was giving you a query form.  You should use the actual table and column
names in your schema…

David J.

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