>>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.

Are you sure upper(alltrim(field))=="" is Rushmore optimizable? Wouldn't you need an index on upper(alltrim(field)), which is a bad idea anyways? I use field == space(len(field)) instead of empty() to get optimization.