| From: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
|---|---|
| To: | Luca Ferrari <fluca1978(at)gmail(dot)com>, Vijaykumar Jain <vijaykumarjain(dot)github(at)gmail(dot)com> |
| Cc: | pgsql-general <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: order by <tablename> |
| Date: | 2021-06-10 09:00:57 |
| Message-ID: | c73b4066b970347839301d842fdf4f646cd1f0ae.camel@cybertec.at |
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| Lists: | pgsql-general |
On Thu, 2021-06-10 at 10:39 +0200, Luca Ferrari wrote:
> I also realized that this "table to tuples" expansion works for GROUP BY too.
> However, I'm not able to find this documented in GROUP BY, WHERE,
> ORDER BY clauses sections into select documentation
> <fgrouphttps://www.postgresql.org/docs/12/sql-select.html>;. Could be
> my fault, of course.
I don't think it is really documented outside the source, but it is
called a "whole-row reference" and behaves in SQL like composite
data type that belongs to the table.
So ordering is lexicographical, equality is equality of all members,
and don't ask me about IS NULL and IS NOT NULL, else I point you to
https://www.postgresql.org/message-id/flat/48BDABE9-88AB-46E9-BABE-F70DDBFB98BD%40kineticode.com
Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com
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