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

Show all cities and corresponding number of students.
SELECT city_code, COUNT(*) FROM student GROUP BY city_code
SELECT "city_code", COUNT(*) FROM "student" GROUP BY "city_code"