> Helen, tks.
>
> I recreate the UDF like you sugest, and I see in RDB$FUNCTIONS to check
> the name of this UDF and I certificate this is: addday, in
> RDB$FUNCTION_NAME is lower case, but still wrong.
>
> I check the UDF nullif and see this working good.

It shouldn't be lowercase, it should be all uppercase.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com