Date: Tue, 26 Sep 2023 17:31:30 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "David G. Johnston" <david.g.johnston@gmail.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>, postgres-hape@gmx.de,
	pgsql-docs@lists.postgresql.org
Subject: Re: group by can use alias from select list
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On Thu, Sep  7, 2023 at 10:11:00AM -0400, Bruce Momjian wrote:
> We do farther down the docs in the GROUP BY section:
> 
> 	https://www.postgresql.org/docs/devel/sql-select.html
> 
> 	GROUP BY will condense into a single row all selected rows that share
> 	the same values for the grouped expressions. An expression used inside a
> 	grouping_element can be an input column name, or the name or ordinal
> 	number of an output column (SELECT list item), or an arbitrary
> 	expression formed from input-column values. In case of ambiguity, a
> 	                  ------------------------
> 	GROUP BY name will be interpreted as an input-column name rather than an
> 	output column name.
> 
> It says
> 
> *  input column name
> *  output column name or ordinal number
> *  expression formed from input-column values
> 
> Is this too subtle?

Patch applied back to PG 11.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.