select case problem

i have a table with the fields empno (not null) and division_no (null
allowed) what i wanted to do is to do a select case statement such that
when division_no is null itll output 'No division' if its not null itll
output 'with division' unfortunately this statement doesnt work ... i
need help on the correct syntax

select case division_no when null then 'no division' else 'with
division' end from employee;