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

What are the student ids for students over 20 years old?
SELECT stuid FROM student WHERE age > 20
SELECT "stuid" FROM "student" WHERE "age" > 20