Return the id of the staff whose Staff Department Assignment was earlier than that of any Clerical Staff.
SELECT staff_id FROM Staff_Department_Assignments WHERE date_assigned_to  <  (SELECT max(date_assigned_to) FROM Staff_Department_Assignments WHERE job_title_code  =  'Clerical Staff')
SELECT staff_id FROM Staff_Department_Assignments WHERE date_assigned_to  <  (SELECT max(date_assigned_to) FROM Staff_Department_Assignments WHERE job_title_code  =  'Clerical Staff')
[{'staff_id': 5}, {'staff_id': 10}, {'staff_id': 1}, {'staff_id': 8}, {'staff_id': 15}, {'staff_id': 2}, {'staff_id': 9}, {'staff_id': 8}, {'staff_id': 6}, {'staff_id': 6}, {'staff_id': 8}, {'staff_id': 12}, {'staff_id': 7}, {'staff_id': 2}]