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

On Wed, 19 Oct 2005, Dann Corbit wrote:

> > -----Original Message-----
> > From: Terry Fielder [mailto:terry(at)ashtonwoodshomes(dot)com]
> > Sent: Wednesday, October 19, 2005 2:05 PM
> > To: Dann Corbit
> > Cc: Tino Wildenhain; Marc G. Fournier; Richard_D_Levine(at)raytheon(dot)com;
> > pgsql-hackers(at)postgresql(dot)org; pgsql-general(at)postgresql(dot)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.