Date: Mon, 7 Jun 2004 09:52:00 +0200
From: Karel Zak <zakkr@zf.jcu.cz>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-sql@postgresql.org
Subject: Re: Formatting problems with negative intervals, TO_CHAR
Message-ID: <20040607075200.GA28529@zf.jcu.cz>
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	<21474.1086561656@sss.pgh.pa.us>
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On Sun, Jun 06, 2004 at 06:40:56PM -0400, Tom Lane wrote:
> Jeff Boes <jboes@qtm.net> writes:
> > This seems ... well, counter-intuitive at least:
> > (using Pg 7.4.1)
> 
> > # select to_char('4 minutes'::interval -
> > '5 minutes 30 seconds'::interval, 'mi:ss');
> 
> >   to_char
> > ---------
> >   -1:-3
> > (1 row)
> 
> > Why is the trailing zero lost? Why are there two minus signs?
> 
> > I would expect '-1:30'.
> 
> Yeah, me too.  The underlying interval value seems right:
> 
> regression=# select '4 minutes'::interval - '5 minutes 30 seconds'::interval;
>  ?column?
> -----------
>  -00:01:30
> (1 row)
> 
> so I think this is a to_char() bug.  Possibly it's platform-dependent
> --- the roundoff behavior for division with a negative input varies
> across machines.  However I do see the bug on HPUX 10.20 with CVS tip.

 Please, read PostgreSQL docs.

  http://www.postgresql.org/docs/7.4/static/functions-formatting.html

  Warning: to_char(interval, text) is deprecated and should not be
  used in newly-written code. It will be removed in the next version.

    Karel

-- 
 Karel Zak  <zakkr@zf.jcu.cz>
 http://home.zf.jcu.cz/~zakkr/