public inbox for [email protected]  
help / color / mirror / Atom feed
From: Tom Lane <[email protected]>
To: Isaac Morland <[email protected]>
Cc: David G. Johnston <[email protected]>
Cc: David Christensen <[email protected]>
Cc: pgsql-hackers <[email protected]>
Subject: Re: [PATCH] GROUP BY ALL
Date: Mon, 22 Jul 2024 18:43:41 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAMsGm5eUihhgcNqDr1h=PwRZxt=3GUnOHqAhvam8X7j2jioaeQ@mail.gmail.com>
References: <CAHM0NXjz0kDwtzoe-fnHAqPB1qA8_VJN0XAmCgUZ+iPnvP5LbA@mail.gmail.com>
	<CAKFQuwY0vhNG8T+pC3BQJurFi3NN_L1KbEPGagRN3V5nKZcpDQ@mail.gmail.com>
	<CAMsGm5eUihhgcNqDr1h=PwRZxt=3GUnOHqAhvam8X7j2jioaeQ@mail.gmail.com>

Isaac Morland <[email protected]> writes:
> And for when this might be useful, the syntax for it already exists,
> although a spurious error message is generated:

> odyssey=> select (uw_term).*, count(*) from uw_term group by uw_term;
> ERROR:  column "uw_term.term_id" must appear in the GROUP BY clause or be
> used in an aggregate function
> LINE 1: select (uw_term).*, count(*) from uw_term group by uw_term;
>                 ^

> I'm not sure exactly what's going on here

The SELECT entry is expanded into "uw_term.col1, uw_term.col2,
uw_term.col3, ...", and those single-column Vars don't match the
whole-row Var appearing in the GROUP BY list.  I guess if we
think this is important, we could add a proof rule saying that
a per-column Var is functionally dependent on a whole-row Var
of the same relation.  Odd that the point hasn't come up before
(though I guess that suggests that few people try this).

			regards, tom lane






view thread (6+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: [PATCH] GROUP BY ALL
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox