You can emulate what you want using the execute statement syntax in
any PSQL (trigger or stored procedure) block, however it is mostly
unnecessary.

Parameters are pseudo-values, not variables. You can generate the
ideal plan for a query using its parameters, but there is no way to
determine the query plan for

SELECT C.NOME FROM CUSTOMERS AS C WHERE :pCode IS NULL OR C.CODIGO =
:pCode;

In this case, you are trying to use pCode as a field name, sort of
like WHERE ID IS NULL. If ID is indexed, then the index could be used
to assist the query.

A Null parameter is not the problem here.

SELECT C.NOME FROM CUSTOMERS AS C WHERE C.CODIGO = :pCode;

Will work fine if :pCode is sent through as null. There may be a case
for an enhancement request to allow a form of find/replace variables,
but it is not available now.

Adam







--- In firebird-support@yahoogroups.com, Fabrício Fadel Kammer
<ffkammer@c...> wrote:

>
> Thanks Jason,
>
> It's I can do this in oracle and I couldn't doing on firebird...
>
> Regards
>
> Fabrício
>
> -----Mensagem original-----
> De: firebird-support@yahoogroups.com
> [mailto:firebird-support@yahoogroups.com] Em nome de Jason Dodson
> Enviada em: quinta-feira, 5 de janeiro de 2006 13:44
> Para: firebird-support@yahoogroups.com
> Assunto: Re: [firebird-support] Null and parameters
>
>
> You cant use a parameter in place of a field name. Its not quite
> find-and-replace.
>
> Jason
>
> Fabrício Fadel Kammer wrote:
> > Hi all,
> >
> > I'm with another doubt here!
> >
> > Can't I use the NULL for parameters comparison like bellow?
> >
> > SELECT C.NOME FROM CUSTOMERS AS C WHERE :pCode IS NULL OR C.CODIGO =
> > :pCode;
> >
> > In this situation I want to select all customers if the pCode
> parameter
> > is NULL or just one customer if the :pCode parameter was informed.
> >
> > Thanks again,
> >
> > Fabrício F. Kammer
> > Conchal/SP Brazil
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >
> > Visit http://firebird.sourceforge.net and click the Resources item
> > on the main (top) menu. Try Knowledgebase and FAQ links !
> >
> > Also search the knowledgebases at http://www.ibphoenix.com
> >
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
>
>
> --
> The information transmitted herewith is sensitive information intended
> only for use to the individual or entity to which it is addressed. If
> the reader of this message is not the intended recipient, you are hereby
> notified that any review, retransmission, dissemination, distribution,
> copying or other use of, or taking of any action in reliance upon, this
> information is strictly prohibited. If you have received this
> communication in error, please contact the sender and delete the
> material from your computer.
>
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Visit http://firebird.sourceforge.net and click the Resources item
> on the main (top) menu. Try Knowledgebase and FAQ links !
>
> Also search the knowledgebases at http://www.ibphoenix.com
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
>
>
>
> _____
>
> YAHOO! GROUPS LINKS
>
>
>
> * Visit your group "firebird-support
> <http://groups.yahoo.com/group/firebird-support> " on the web.
>
>
> * To unsubscribe from this group, send an email to:
> firebird-support-unsubscribe@yahoogroups.com
> <mailto:firebird-support-unsubscribe@yahoogroups.com?subject=Unsubscribe
> >
>
>
> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> Service <http://docs.yahoo.com/info/terms/> .
>
>
> _____
>
>
>
>
> [Non-text portions of this message have been removed]
>