CREATE TABLE PersonFriend (name VARCHAR2, friend VARCHAR2, year NUMBER)
CREATE TABLE Person (name VARCHAR2, age NUMBER, city CLOB, gender CLOB, job CLOB)

Return a histogram on how old is each gender, on average?, and could you show bars in asc order please?
SELECT gender, AVG(age) FROM Person GROUP BY gender ORDER BY gender
SELECT "gender", AVG("age") FROM "Person" GROUP BY "gender" ORDER BY "gender"