Database: assets_maintenance
Question: Which skill is used in fixing the most number of faults? List the skill id and description.
SQL:
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