Check Using Rushmore Query Optimization to Speed Data Access in Help and check the note.

Interestingly, the google search gives a link to VFP8 Help, not to VFP9.

>Thanks Sergey,
>
>That helps me get a clearer picture. I made a slight alteration because the where clause seems to handle the same thing as NVL(). When you say it is not optimizable do you mean just using the EMPTY() function? Is there information somewhere on optimizable and non-optimizable functions? I changed it to look as follows:

<snip>