What is the skill code for skill id 1, 2 and 3 ?
select skill_id, skill_code from skills where skill_id = 1 or skill_id = 2 or skill_id = 3
How many ids are in part_fault_id...Tell me total number
select count ( distinct part_fault_id ) from skills_required_to_fix
What is the skill description for skill id 3 ?
select skill_description from skills where skill_id = 3
Which skill is used in fixing the most number of faults ? List the skill id and description
select t1.skill_id, t1.skill_description from skills as t1 join skills_required_to_fix as t2 on t1.skill_id = t2.skill_id group by t1.skill_id order by count ( * ) desc limit 1