Which actors appeared in musical with name "Wicked"?
select t1.name from actor as t1 join musical as t2 on t1.musical_id = t2.musical_id where t2.name = "Wicked"
What about "The Phantom of the Opera"?
select t1.name from actor as t1 join musical as t2 on t1.musical_id = t2.musical_id where t2.name = "The phantom of the Opera"