CREATE TABLE employee (eid NUMBER, name VARCHAR2, salary NUMBER)
CREATE TABLE aircraft (aid NUMBER, name VARCHAR2, distance NUMBER)
CREATE TABLE certificate (eid NUMBER, aid NUMBER)
CREATE TABLE flight (flno NUMBER, origin VARCHAR2, destination VARCHAR2, distance NUMBER, departure_date DATE, arrival_date DATE, price NUMBER, aid NUMBER)

Bar chart of the total number from each origin, could you sort total number in desc order?
SELECT origin, COUNT(*) FROM flight GROUP BY origin ORDER BY COUNT(*) DESC
SELECT "origin", COUNT(*) FROM "flight" GROUP BY "origin" ORDER BY COUNT(*) DESC