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

Find the average age for students with different sex in a bar chart, rank x axis in descending order.
SELECT Sex, AVG(Age) FROM Student GROUP BY Sex ORDER BY Sex DESC
SELECT "Sex", AVG("Age") FROM "Student" GROUP BY "Sex" ORDER BY "Sex" DESC NULLS LAST