For each position, how much did each player practice?
select t2.hs, t1.ppos from tryout as t1 join player as t2 on t1.pid = t2.pid group by t1.ppos
What is the minimum for each position?
select min(t2.hs), t1.ppos from tryout as t1 join player as t2 on t1.pid = t2.pid group by t1.ppos