CREATE TABLE has_allergy (stuid NUMBER, allergy CLOB)
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)

How many different advisors are listed?
SELECT COUNT(DISTINCT advisor) FROM student
SELECT COUNT(DISTINCT "advisor") FROM "student"