Re: Extract only maximum date from column

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От David G. Johnston
Тема Re: Extract only maximum date from column
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Msg-id CAKFQuwaTe2vX30erug=2v0G5BL3G=vYvwNC-8jJFkKUe3EimEQ@mail.gmail.com
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Ответ на Re: Extract only maximum date from column  (Rich Shepard <rshepard@appl-ecosys.com>)
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On Thursday, December 4, 2025, Rich Shepard <rshepard@appl-ecosys.com> 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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