Use of Expressions That Limit Data Output In Query Results

[mezuhlke]

I have used the following argument to limit the results I send to a report to
show current employees (and room occupants) at my work site. Use of the "Is
Null" expression effectively eliminates the person departing from my room and
roll call reports but it also does not allow my reports to show new occupants
of of the vacated rooms; how do I modify the argument below to allow me to
populate vacancies and show the results on my reports?

Thank you,
Marcus

SELECT [Personnel Data Query].Employee_SAP_Number, [Personnel
Data].Last_Name, [Personnel Data].First_Name, [Room Assignment].[Room
Number], [Room Assignment].[Assignment Date]
FROM ([Personnel Data Query] INNER JOIN [Personnel Data] ON [Personnel Data
Query].Employee_SAP_Number = [Personnel Data].Employee_SAP_Number) INNER JOIN
[Room Assignment] ON [Personnel Data].Employee_SAP_Number = [Room
Assignment].[Employee SAP Number]
WHERE ((([Room Assignment].[Departure Date]) Is Null));