SELECT StuID FROM Has_allergy GROUP BY StuID HAVING count(*)  >=  2
What are the students ids of students who have more than one allergy?
SELECT StuID FROM Has_allergy GROUP BY StuID HAVING count ( * ) > = 2
select stuid from has_allergy group by stuid having count ( * ) > = value
What are the students ids of students who have more than one allergy ?