From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
cc: "David G. Johnston" <david.g.johnston@gmail.com>,
        Guyren Howe <guyren@gmail.com>,
        Pg Docs <pgsql-docs@lists.postgresql.org>
Subject: Re: Please provide examples of rows from
In-reply-to: <20200920003910.GA22746@momjian.us>
References: <158638264419.662.2482095087061084020@wrigleys.postgresql.org>
 <20200904014618.GB13932@momjian.us>
 <CAKFQuwbBDr22KJRyJQRECO_XU6cyouwz3ocn0Tv4JgG4Gm5hMQ@mail.gmail.com>
 <20200920003910.GA22746@momjian.us>
Comments: In-reply-to Bruce Momjian <bruce@momjian.us>
	message dated "Sat, 19 Sep 2020 20:39:10 -0400"
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Date: Sat, 19 Sep 2020 20:49:53 -0400
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Bruce Momjian <bruce@momjian.us> writes:
> 	test=3D> \df pg_get_keywords
> 	                                                                   List=
 of functions
> 	   Schema   |      Name       | Result data type |                     =
                 Argument data types                                      =
| Type
> 	------------+-----------------+------------------+---------------------=
--------------------------------------------------------------------------=
+------
> 	 pg_catalog | pg_get_keywords | SETOF record     | OUT word text, OUT c=
atcode "char", OUT barelabel boolean, OUT catdesc text, OUT baredesc text =
| func
> 	(1 row)

> 	test=3D> select * from pg_get_keywords() AS f(word text);
> -->	ERROR:  a column definition list is only allowed for functions retur=
ning "record"
> 	LINE 1: select * from pg_get_keywords() AS f(word text);

Yeah, this error message needs some help.  With a function having
multiple OUT parameters, the prorettype is indeed "record", but
the specific record type is implied by the OUT parameters so you
do not need to (and can't) specify it in the query.

The point of the AS feature is to allow specifying the concrete
record type for record-returning functions that don't have a
predefined result record type, like dblink().

I think this error text was written before we had multiple OUT
parameters, so it was okay at the time; but now it needs to be
more precise.

			regards, tom lane