Query Public Variable and Is Null Help

[2ShotLatte]

Greetings

I have a query that uses a public variable (varHall). The query returns only records where tblStaff.Hall and varHall are equal. I also want the query to return all records if varHall is null. Here's what I've done so far, but I'm stumped after that.

Select tblStaff.StaffID, tbleHall
From tblStaff
WHERE (((tblStaff.Hall)=varHall()));

I've tried IsNull, but not sure if I'm getting the syntax right or just completely off. I'm hoping some Access Gods out there can help.

Thanks!
Steve

 

[2ShotLatte]

Fo'gitaboutit.
Word out the problem - was missing last bit of work

WHERE (((tblStaff.HallID)=qryHall())) OR ((([tblStaff].[HallID]=qryHall()) Is Null));