What are the names of all players who participated in tryouts?
select t1.pname from player as t1 join tryout as t2 on t1.pid = t2.pid
Which of those received a yes?
select t1.pname from player as t1 join tryout as t2 on t1.pid = t2.pid where t2.decision = 'yes'
How many hours did each of them practice for?
select t1.pname, t1.hs from player as t1 join tryout as t2 on t1.pid = t2.pid where t2.decision = 'yes'