From: Tom Lane <tgl@sss.pgh.pa.us>
To: Markus Bertheau ☭ <twanger@bluetwanger.de>
Cc: Joe Conway <mail@joeconway.com>
Cc: pgsql-sql@postgresql.org
Cc: pgsql-hackers@postgresql.org
Subject: Re: ARRAY() returning NULL instead of ARRAY[] resp. {}
Date: Mon, 06 Jun 2005 10:44:49 -0400
Message-ID: <25974.1118069089@sss.pgh.pa.us> (raw)
In-Reply-To: <1118067445.5506.6.camel@dicaprio.akademie1.de>
References: <1116873219.7306.0.camel@localhost.localdomain>
<42923762.7010708@joeconway.com>
<16774.1116907560@sss.pgh.pa.us>
<1118067445.5506.6.camel@dicaprio.akademie1.de>
Markus Bertheau =?UTF-8?Q?=E2=98=AD?= <twanger@bluetwanger.de> writes:
> By analogy, array_upper('{}'::TEXT[], 1) should return 0 instead of
> NULL.
No, that doesn't follow ... we've traditionally considered '{}' to
denote a zero-dimensional array. A 1-D array of no elements is
'[1:0]={}', just as Joe shows ... or at least it would be except
for an overenthusiastic error check:
regression=# select '[1:0]={}' :: int[];
ERROR: upper bound cannot be less than lower bound
I think this should be a legal boundary case. In general, it should be
possible to form zero-size arrays of any number of dimensions.
regards, tom lane
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: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, twanger@bluetwanger.de, mail@joeconway.com, pgsql-hackers@postgresql.org
Subject: Re: ARRAY() returning NULL instead of ARRAY[] resp. {}
In-Reply-To: <25974.1118069089@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox