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

Give the number of students living in either HKG or CHI.
SELECT COUNT(*) FROM student WHERE city_code = "HKG" OR city_code = "CHI"
SELECT COUNT(*) FROM "student" WHERE "CHI" = "city_code" OR "HKG" = "city_code"