CREATE TABLE ship (Ship_ID INT, Name TEXT, Type TEXT, Nationality TEXT, Tonnage INT)
CREATE TABLE mission (Mission_ID INT, Ship_ID INT, Code TEXT, Launched_Year INT, Location TEXT, Speed_knots INT, Fate TEXT)

Give me a bar chart for mean tonnage of each type, show by the Y in asc.
SELECT Type, AVG(Tonnage) FROM ship GROUP BY Type ORDER BY AVG(Tonnage)
SELECT "Type", AVG("Tonnage") FROM "ship" GROUP BY "Type" ORDER BY AVG("Tonnage") NULLS FIRST