How many staff members have the first name Christop.
select count(*) from staff where staff_first_name = "Christop"
What problem are these members authorized to close!
select * from problems as t1 join staff as t2 on t1.closure_authorised_by_staff_id = t2.staff_id where t2.staff_first_name = "Christop"
How about what problems have these members reported!
select * from problems as t1 join staff as t2 on t1.reported_by_staff_id = t2.staff_id where t2.staff_first_name = "Christop"
List just the problem descriptions for each?
select t1.problem_description from problems as t1 join staff as t2 on t1.reported_by_staff_id = t2.staff_id where t2.staff_first_name = "Christop"