list the name of staff who has been assigned multiple jobs?
SELECT T1.staff_name FROM staff AS T1 JOIN staff_department_assignments AS T2 ON T1.staff_id   =   T2.staff_id GROUP BY T2.staff_id HAVING COUNT  ( * )   >  1
staff who has been assigned multiple jobs refers to staff with more than one entry in staff_department_assignments; list the name refers to SELECT staff_name;