CREATE TABLE Person (name VARCHAR, age INT, city TEXT, gender TEXT, job TEXT)
CREATE TABLE PersonFriend (name VARCHAR, friend VARCHAR, year INT)

Bar graph to show the average of age from different gender, and I want to show by the bars in desc.
SELECT gender, AVG(age) FROM Person GROUP BY gender ORDER BY gender DESC
SELECT "gender", AVG("age") FROM "Person" GROUP BY "gender" ORDER BY "gender" DESC NULLS LAST