Database: department_store
Question: What is the id and name of the staff who has been assigned for the smallest difference between date_assigned_to and date_assigned_from?
SQL: 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