Database: sakila_1
Question: Which film actors (actresses) played a role in more than 30 films? List his or her first name and last name.
SQL: select t2.first_name ,  t2.last_name from film_actor as t1 join actor as t2 on t1.actor_id  =  t2.actor_id group by t2.actor_id having count(*)  >  30