How do I query empty date fields?

[pdbowling]

Hello all.
I need to mine out entries in a database where the date field was left blank so it can be entered (why didn't they make it a required field in the first place). When I try to query on a date field with criteria = to nil or empty I get a type mismatch. Anybody know what my criteria should be?
Thanks
PB

 

[FoFa]

Is Null

 

[pdbowling]

Thank you.

Thank you.
PB