Concatenation of Name field of the user belonging to specific department without affecting users

[ark257]

I have written a business rule on sys_user table

before query

condition: Department.name=='XYZ'

var firstName = g_form.getValue('first_name');
var lastName = g_form.getValue('last_name');
var Name = firstName + ' ' + lastName;
g_form.setValue('Name', Name);

But the condition is returning null value when business rule is ran