Re: How do I change sort order behavious with nulls

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: charlie clark <charlie(at)begeistert(dot)org>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: How do I change sort order behavious with nulls
Date: 2005-02-19 18:01:07
Message-ID: 20050219180107.GB15226@wolff.to
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

On Sat, Feb 19, 2005 at 18:04:32 +0100,
charlie clark <charlie(at)begeistert(dot)org> wrote:
> Dear list,
>
> is there a simple way to change the way ORDER BY works on columns with
> NULLs? I can understand the need for default behaviour but there must be
> cases when this is undesirable. I have such a query with the NULLs arising
> as the result of an OUTER JOIN and I would like to ORDER BY DESC with
> NULLs treated as <= 0. I've already tried a few things but nothing's
> working so far.

Presumably what you mean is that you want NULLs to be output last when
doing a descending order by.

You can do this using ORDER BY whatever IS NULL ASC, whatever DESC .

If you really mean you want to treat them as less than or equal to
0, then you can pick such a value and use coalesce to change NULLs
to that value in the ORDER BY clause.

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Bruno Wolff III 2005-02-19 18:07:15 Re: Group By and wildcards...
Previous Message Jon Lapham 2005-02-19 17:59:52 Re: Group By and wildcards...