>I have found that "" will match almost anything when comparing. So I either use
>
>!EMPTY() .AND. next_condition...
>
>or, I use the == comparison operator...

EMPTY() is not Rushmore optimizable unless you add indexes on EMPTY() which is a bad idea because their selectivity is low.

== is best. For instance you can use upper(alltrim(field))=="" to find all records with empty(field). It works in both SQL and Rushmore.

I only use empty() if I am not doing anything involving rushmore or sql.