Show ID and first and last name of Engineer who has visited the most times.
SELECT T1.engineer_id ,  T1.first_name ,  T1.last_name FROM Maintenance_Engineers AS T1 JOIN Engineer_Visits AS T2 on T1.engineer_id  =  T2.engineer_id GROUP BY T1.engineer_id ORDER BY count ( * )  DESC LIMIT 1
Engineer who has visited the most times refers to MAX(COUNT(visits)); show ID refers to engineer_id; first and last name refers to first_name and last_name;