CREATE TABLE staff (staff_name VARCHAR2, staff_id VARCHAR2)
CREATE TABLE staff_department_assignments (staff_id VARCHAR2)

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
SELECT "T1"."staff_name" FROM "staff" "T1" JOIN "staff_department_assignments" "T2" ON "T1"."staff_id" = "T2"."staff_id" GROUP BY "T2"."staff_id" HAVING COUNT(*) > 1