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

Show different types of ships and the average tonnage of ships of each type in a pie chart.
SELECT Type, AVG(Tonnage) FROM ship GROUP BY Type
SELECT "Type", AVG("Tonnage") FROM "ship" GROUP BY "Type"