Jim,

You're quoting out of context. I was referring to "already open tables or cursors".
The tables, that were not already opened, are opened by VFP SQL Engine and left open after the query is completed.

>
>"and closes after the query".
>
>Is that right? I thought that if it was not already opened, you were left with an opened file.
>

>>VFP SQL Engine does not use already open tables or cursors in a query. It open them again similar to USE..AGAIN and closes after the query is complete. As result, active, index, filters, etc. on already open tables have no effect on the query.
>>VFP uses Rushmore optimization to speed up queries. In short, it uses existing or temporary indexes (if it can) to process only data that match WHEN or JOIN conditions. You cannot use queries effectively w/o understanding how Rushmore optimization works.