Show me the id and name of a fault that needs the least number of skills to be fixed.
select t1.part_id, t1.part_name from parts as t1 join part_faults as t2 on t1.part_id = t2.part_id join skills_required_to_fix as t3 on t2.part_fault_id = t3.part_fault_id group by t1.part_id order by count(*) asc limit 1
How about the fault that requires the most number of skills to fix?
select t1.part_id, t1.part_name from parts as t1 join part_faults as t2 on t1.part_id = t2.part_id join skills_required_to_fix as t3 on t2.part_fault_id = t3.part_fault_id group by t1.part_id order by count(*) desc limit 1