CREATE TABLE dorm (dormid NUMBER, dorm_name CLOB, student_capacity NUMBER, gender CLOB)
CREATE TABLE student (stuid NUMBER, lname CLOB, fname CLOB, age NUMBER, sex CLOB, major NUMBER, advisor NUMBER, city_code CLOB)
CREATE TABLE lives_in (stuid NUMBER, dormid NUMBER, room_number NUMBER)
CREATE TABLE has_amenity (dormid NUMBER, amenid NUMBER)
CREATE TABLE dorm_amenity (amenid NUMBER, amenity_name CLOB)

How many students are from each city, and which cities have more than one cities?
SELECT COUNT(*), city_code FROM student GROUP BY city_code HAVING COUNT(*) > 1
SELECT COUNT(*), "city_code" FROM "student" GROUP BY "city_code" HAVING COUNT(*) > 1