CREATE TABLE staff (staff_id VARCHAR, staff_name VARCHAR)
CREATE TABLE Staff_Department_Assignments (staff_id VARCHAR)

Find the id and name of the staff who has been assigned for the shortest period.
SELECT T1.staff_id, T1.staff_name FROM staff AS T1 JOIN Staff_Department_Assignments AS T2 ON T1.staff_id = T2.staff_id ORDER BY date_assigned_to - date_assigned_from LIMIT 1
SELECT "T1"."staff_id", "T1"."staff_name" FROM "staff" AS "T1" JOIN "Staff_Department_Assignments" AS "T2" ON "T1"."staff_id" = "T2"."staff_id" ORDER BY "date_assigned_to" - "date_assigned_from" NULLS FIRST LIMIT 1