Re: casting NULLs: WAS: Oracle8i Left Join Question

From: Neil Zanella <nzanella_at_cs.mun.ca>
Date: 21 Nov 2001 16:16:54 -0800
Message-ID: <b68d2f19.0111211616.53cd8a48@posting.google.com>

Nicholas Carey <ncarey_at_speakeasy.org> wrote in message news:<Xns915FB970E310Fncareyspeakeasyorg_at_207.126.101.92>...

> select foo.id foo_id ,
> bar.id bar_id
> from foo
> join bar on bar.id = foo.id
> UNION
> select foo.id foo_id ,
> to_number(NULL) bar_id
> from foo
> where not exists ( select * from bar
> where bar.id = foo.id
> )

Thank you for pointing out that Oracle has a to_number() function. This solves the problem but the resulting code is not portable in the sense that it will produce errors with database systems other than Oracle. Other DBMS perform the cast automatically. After all what else could the user have in mind when placing a NULL in some column field? I strongly believe that is should be allowed.

Thank you for pointing out the bugfix,

Neil Received on Wed Nov 21 2001 - 18:16:54 CST