From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?UTF-8?B?RWzDrWFzIERhdmlk?= <elias.moreno.tec@gmail.com>
cc: pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: Default order of select datname from pg_database
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Comments: In-reply-to =?UTF-8?B?RWzDrWFzIERhdmlk?=
 <elias.moreno.tec@gmail.com>
 message dated "Sat, 19 Apr 2014 02:49:14 -0430"
Date: Sat, 19 Apr 2014 11:17:35 -0400
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=?UTF-8?B?RWzDrWFzIERhdmlk?= <elias.moreno.tec@gmail.com> writes:
> By any change, does the following query have an "order by" by default when
> omitted?:

> select datname from pg_database;

No.  No SQL query ever has a "default" order by.

> I executed that query against one of my servers and while looking at the
> names it seems complety random, the order is always the same, for instance:

An unqualified query is typically going to result in a sequential scan
of the table, so what you're seeing is the current physical order of the
tuples.  This might change after adding/deleting/changing the properties
of a database.

			regards, tom lane


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