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

A bar chart about what is average age for different job title?, and rank by the the average of age in desc.
SELECT job, AVG(age) FROM Person GROUP BY job ORDER BY AVG(age) DESC
SELECT "job", AVG("age") FROM "Person" GROUP BY "job" ORDER BY AVG("age") DESC NULLS LAST