CREATE TABLE Dorm_amenity (amenid NUMBER, amenity_name VARCHAR2)
CREATE TABLE Lives_in (stuid NUMBER, dormid NUMBER, room_number NUMBER)
CREATE TABLE Has_amenity (dormid NUMBER, amenid NUMBER)
CREATE TABLE Dorm (dormid NUMBER, dorm_name VARCHAR2, student_capacity NUMBER, gender VARCHAR2)
CREATE TABLE Student (StuID NUMBER, LName VARCHAR2, Fname VARCHAR2, Age NUMBER, Sex VARCHAR2, Major NUMBER, Advisor NUMBER, city_code VARCHAR2)

What are average ages for students living in each city? Return a bar chart, could you sort names in desc order?
SELECT city_code, AVG(Age) FROM Student GROUP BY city_code ORDER BY city_code DESC
SELECT "city_code", AVG("Age") FROM "Student" GROUP BY "city_code" ORDER BY "city_code" DESC