CREATE TABLE has_allergy (stuid DECIMAL, allergy TEXT)
CREATE TABLE allergy_type (allergy TEXT, allergytype TEXT)
CREATE TABLE student (stuid DECIMAL, lname TEXT, fname TEXT, age DECIMAL, sex TEXT, major DECIMAL, advisor DECIMAL, city_code TEXT)

Show all student IDs who have at least two allergies.
SELECT stuid FROM has_allergy GROUP BY stuid HAVING COUNT(*) >= 2
SELECT "stuid" FROM "has_allergy" GROUP BY "stuid" HAVING COUNT(*) >= 2