Records not showing when a role id doesn't exist

The following is the column that I'm working with.

RoleID(numeric(10,0),not null)

I have the following formula

If {ROLES_mda.RoleID} = 1

Then {STAFF_mda.StaffLastName}&", "& {STAFF_mda.StaffFirstName}

I tried the following in my record selection and it is not showing the rows that don't have a role # 1.

(IsNull({ROLES_mda.RoleID}) or

{ROLES_mda.RoleID} = 1) and

How can the get the rows to show?