WHAT IS LAST NAME OF THE STAFF WHO HAS HANDLED THE FIRST EVER COMPLAINT?
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
THE FIRST NAME OF THE STAFF WHO HAS HANDLED THE LAST COMPLAINT
select t1.first_name from staff as t1 join complaints as t2 on t1.staff_id = t2.staff_id order by t2.date_complaint_raised desc limit 1