Question: Find the names of states that have some college students playing in the mid position but not in the goalie position.
SQL: SELECT T1.state FROM college AS T1 JOIN tryout AS T2 ON T1.cName  =  T2.cName WHERE T2.pPos  =  'mid' EXCEPT SELECT T1.state FROM college AS T1 JOIN tryout AS T2 ON T1.cName  =  T2.cName WHERE T2.pPos  =  'goalie'