At 09:38 AM 23/09/2004 -0300, you wrote:
Sorry, just noticed this:

> I'm (still) using Firebird 1.0.3.

You can use the UDF sNVL:

declare external function snvl
varchar(100) by descriptor, varchar(100) by descriptor,
varchar(100) by descriptor returns parameter 3
entry_point 'sNvl' module_name 'fbudf';

SELECT C FROM T
WHERE X = :A
AND sNvl(Y, '' ) = :B)


./heLen