Re: to_char and '=' weirdness

On Thu, Aug 08, 2002 at 02:11:55PM +0200, Karel Zak wrote:
> On Thu, Aug 08, 2002 at 04:48:24AM -0700, Ludwig Lim wrote:
> > 
> > > which would appear to indicate that to_char actually
> > > yields the string
> > > '04109'. Why doesn't the '=' operator work then?
> > 
> >   I tried running a test sql statement
> >  select(length(to_char(99,'00000')))
> >  It return six.
> > 
> >  I think that postgreSQL put a leading blank to
> > indicate that it is a positive number (not sure, just
> > my opinion)
> 
>  Right.
> 
> >   try using :
> >    
> >   select to_char(plz,'00000')
> >   from andresses 
> >   where trim(to_char(plz,'00000'))='04109'
> 
>  use FM instead trim(): to_char(plz,'FM00000')
> 
>  ...and please, better read  docs :-)

Well, I just looked again and couldn't find it. Mostly I use Bruce's
excellent book (pdf version from November 2000), which at least mentions
to_char. I just went to

http://www.de.postgresql.org/users-lounge/docs/7.2/postgres/

and looked under data types and type conversion, to no avail.

Where is this documented?

Regards, Frank