From 1b5a00450acb34d4aa4565aa54fe79c6676f8236 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Tue, 26 Sep 2023 17:31:06 -0400
Subject: [PATCH] doc:  mention GROUP BY columns can reference target col
 numbers

Reported-by: hape <postgres-hape@gmx.de>

Discussion: https://postgr.es/m/168871536004.379168.9352636188330923805@wrigleys.postgresql.org

Backpatch-through: 11
---
 doc/src/sgml/ref/select.sgml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e641..42d78913cf9 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -131,6 +131,9 @@ TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
       eliminates groups that do not satisfy the given condition.  (See
       <xref linkend="sql-groupby"/> and
       <xref linkend="sql-having"/> below.)
+      Although query output columns are nominally computed in the next
+      step, they can also be referenced (by name or ordinal number)
+      in the <literal>GROUP BY</literal> clause.
      </para>
     </listitem>