Which film actor (actress) starred the most films? List his or her first name, last name and actor id.
SELECT T2.first_name ,  T2.last_name ,  T2.actor_id FROM film_actor AS T1 JOIN actor AS T2 ON T1.actor_id  =  T2.actor_id GROUP BY T2.actor_id ORDER BY count(*) DESC LIMIT 1
actor (actress) who starred in the most films refers to MAX(COUNT(film appearances)); listing first name, last name, and actor id involves selecting T2.first_name, T2.last_name, T2.actor_id; joining tables film_actor and actor on actor_id is required to relate actors to their film appearances;