What is the last name of the staff who has handled the first ever complaint?
create table staff (last_name varchar, staff_id varchar, PRIMARY KEY (last_name)); create table complaints (staff_id varchar, date_complaint_raised varchar, PRIMARY KEY (staff_id))
select t1.last_name from staff as t1 join complaints as t2 on t1.staff_id = t2.staff_id order by t2.date_complaint_raised limit 1