Thanks, Sergey.

It's too bad. It's the perfect solution for what I need in this case. It's a table for tracking timeclock punches - one record for each in / out pair. If the 'Out' field is NULL, then the employee is assumed punched in. The table will contain a lot of records, and the majority of the records will not have a NULL value in the 'Out' field.

In your view, would I be better off using something like this?
INDEX ON pk_employee FOR ISNULL(out) TAG InEmps

Thanks.

-Matt