From: | Manfred Koizar <mkoi-pg(at)aon(dot)at> |
---|---|
To: | gss+pg(at)cs(dot)brown(dot)edu |
Cc: | PostgreSQL general mailing list <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: select min row in a group |
Date: | 2002-06-28 22:27:41 |
Message-ID: | 48ophu8t7k4rsklf3go4fp69hmkqoslptp@4ax.com |
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Lists: | pgsql-general |
On Fri, 28 Jun 2002 17:56:17 -0400, Gregory Seidman
<gss+pg(at)cs(dot)brown(dot)edu> wrote:
>This is really an SQL question, not specific to PostgreSQL.
Greg,
but the answer is specific to PostgreSQL :-)
>For each ext_id (which references something in another table), I want to
>find the row with the minimum value.
>I feel like there has to be a way to do it without a nested query, probably
>using GROUP BY. Any thoughts?
If you only need ext_id and value, this should work with most SQL
dialects:
SELECT ext_id, min(value)
FROM ValTable
GROUP BY ext_id;
If you need all the other columns, use this PostgreSQL extension:
SELECT DISTINCT ON (ext_id) ext_id, value, ...
FROM ValTable
ORDER BY ext_id, value;
Servus
Manfred
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