query: SELECT StuID FROM Participates_in INTERSECT SELECT StuID FROM Student WHERE age  <  20
question: What are the ids of the students who are under 20 years old and are involved in at least one activity.
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: What are the ids of the students who are under 20 years old and are involved in at least one activity.