query: SELECT StuID FROM Participates_in INTERSECT SELECT StuID FROM Student WHERE age  <  20
question: Show the ids for all the students participate in an activity and are under 20.
query_toks: SELECT StuID FROM Participates_in INTERSECT SELECT StuID FROM Student WHERE age < 20
query_toks_no_value: select stuid from participates_in intersect select stuid from student where age < value
question_toks: Show the ids for all the students participate in an activity and are under 20.