Received: from malur.postgresql.org ([217.196.149.56])
 by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from
 <pgsql-docs-owner+M8409=pgsql+2Ddocs=arkaria.postgresql.org@postgresql.org>)
 id 1Zqlky-0007dE-HX
 for pgsql-docs@arkaria.postgresql.org; Mon, 26 Oct 2015 17:40:29 +0000
Received: from localhost ([127.0.0.1] helo=postgresql.org)
 by malur.postgresql.org with smtp (Exim 4.84) (envelope-from
 <pgsql-docs-owner+M8409=pgsql+2Ddocs=arkaria.postgresql.org@postgresql.org>)
 id 1Zqlky-0003nw-0Q
 for pgsql-docs@arkaria.postgresql.org; Mon, 26 Oct 2015 17:40:28 +0000
Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29])
 by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256)
 (Exim 4.84) (envelope-from <quabla@hemio.de>) id 1Zqedy-00061Q-SP
 for pgsql-docs@postgresql.org; Mon, 26 Oct 2015 10:04:46 +0000
Received: from mail.hemio.de ([144.76.93.186])
 by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256)
 (Exim 4.84) (envelope-from <quabla@hemio.de>) id 1Zqedv-0000Hq-RS
 for pgsql-docs@postgresql.org; Mon, 26 Oct 2015 10:04:46 +0000
X-Original-To-Masked: <masked>
X-Original-To-Masked: <masked>
Received: from user.client (localhost [144.76.93.186])
 by mail.hemio.de (Postfix) with ESMTPSA id 4253F9B;
 Mon, 26 Oct 2015 11:04:41 +0100 (CET)
Message-ID: <562DFAB8.9050507@hemio.de>
Date: Mon, 26 Oct 2015 11:04:40 +0100
From: Michael Herold <quabla@hemio.de>
User-Agent: Mozilla/5.0 (X11; Linux i686;
 rv:31.0) Gecko/20100101 Icedove/31.8.0
MIME-Version: 1.0
To: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-docs@postgresql.org
Subject: Re: ARRAY[1] || NULL <> array_append(ARRAY[1], NULL)
References: <559DC0CE.90900@hemio.de> <32402.1436450457@sss.pgh.pa.us>
In-Reply-To: <32402.1436450457@sss.pgh.pa.us>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 8bit
X-Pg-Spam-Score: -4.2 (----)
List-Archive: <http://archives.postgresql.org/pgsql-docs>
List-Help: <mailto:majordomo@postgresql.org?body=help>
List-ID: <pgsql-docs.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@postgresql.org>
List-Post: <mailto:pgsql-docs@postgresql.org>
List-Subscribe: <mailto:majordomo@postgresql.org?body=sub%20pgsql-docs>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-docs>
X-Mailing-List: pgsql-docs
Precedence: bulk
Sender: pgsql-docs-owner@postgresql.org

I just got confused by another behavior of the || operator. I thought it 
might be appropriate to report it here.

The docs say "the result retains the lower bound subscript of the 
left-hand operand’s outer dimension" [1]. That's again not true for 
corner cases.

Expected:
# SELECT '{0}'::int[] || '[15:16]={1,2}';
----------
  {0,1,2}

Unexpected (lower bound is untouched):
# SELECT '{}'::int[] || '[15:16]={1,2}';
---------------
  [15:16]={1,2}

Actually, I was looking for a way to reset the index lower bound of an 
array to the default. I didn't found a solution documented anywhere, [2] 
only works for known array sizes. So, it might also be worth stating 
ARRAY(SELECT UNNEST(...)) as a solution?

[1]: <http://www.postgresql.org/docs/9.5/static/arrays.html>
[2]: <http://www.postgresql.org/message-id/40854D0B.6000005@cromwell.co.uk>


-- 
Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-docs