I have an address table with an address_key (1, 2, 3, ect.) where the highest address key is the current address.  I'm trying to pull the record with the highest address key in the selection criteria.  I attempt to use the MAXIMUM function, but I keep getting the error message "A Boolen is required here."  The Address Key field is a number field.  Why do I get this message and is there another way that works to pull the record with the highest address key?