Re: 'a' == 'a ' (Was: RE: [pgsql-advocacy] [GENERAL] Oracle

On Wed, 19 Oct 2005, Dann Corbit wrote:

> > -----Original Message-----
> > From: Terry Fielder [mailto:terry@ashtonwoodshomes.com]
> > Sent: Wednesday, October 19, 2005 2:05 PM
> > To: Dann Corbit
> > Cc: Tino Wildenhain; Marc G. Fournier; Richard_D_Levine@raytheon.com;
> > pgsql-hackers@postgresql.org; pgsql-general@postgresql.org
> > Subject: Re: 'a' == 'a ' (Was: RE: [pgsql-advocacy] [GENERAL] Oracle
> > buysInnobase)
> >
> >
> >
> > Dann Corbit wrote:
> > > Try this query in Oracle, SQL*Server, DB/2, Informix, etc.:
> > >
> > > connxdatasync=# select 1 where cast('a' as varchar(30)) = cast('a '
> as
> > > varchar(30));
> > >  ?column?
> > > ----------
> > > (0 rows)
> > >
> > > I see how you can interpret the SQL Standard to make the above
> response
> > > a correct one.  But is it the response that you would like?
> >
> > When the compared datatypes are VARCHAR: YES
>
> What is the value of doing that?
>
> I can see plenty of harm and absolutely no return.  We are talking about
> blank padding before comparison.  Do you really want 'Danniel '
> considered distinct from 'Danniel  ' in a comparison?  In real life,
> what does that buy you?

It buys you the ability to store things where trailing spaces are
signficant (for example passwords) within the existing limitations of not
having a full set of the collation behavior.