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

Which major has most number of students?
SELECT major FROM student GROUP BY major ORDER BY COUNT(*) DESC LIMIT 1
SELECT "major" FROM "student" GROUP BY "major" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY