What are the player ids of every player whose name starts with D?
select pid from player where pname like 'D%'
Of those, who tried out?
select t1.pid from tryout as t1 join player as t2 on t1.pid = t2.pid where t2.pname like 'D%'
What college did they go to?
select t1.cname from tryout as t1 join player as t2 on t1.pid = t2.pid where t2.pname like 'D%'