CREATE TABLE restaurant_type (restypeid NUMBER, restypename CLOB, restypedescription CLOB)
CREATE TABLE type_of_restaurant (resid NUMBER, restypeid NUMBER)
CREATE TABLE restaurant (resid NUMBER, resname CLOB, address CLOB, rating NUMBER)
CREATE TABLE visits_restaurant (stuid NUMBER, resid NUMBER, time TIME, spent NUMBER)
CREATE TABLE student (stuid NUMBER, lname CLOB, fname CLOB, age NUMBER, sex CLOB, major NUMBER, advisor NUMBER, city_code CLOB)

Which Advisor has most of students? List advisor and the number of students.
SELECT advisor, COUNT(*) FROM student GROUP BY advisor ORDER BY COUNT(advisor) DESC LIMIT 1
SELECT "advisor", COUNT(*) FROM "student" GROUP BY "advisor" ORDER BY COUNT("advisor") DESC FETCH FIRST 1 ROWS ONLY