CREATE TABLE Products (Code INT, Name VARCHAR, Price DECIMAL, Manufacturer INT)
CREATE TABLE Manufacturers (Code INT, Name VARCHAR, Headquarter VARCHAR, Founder VARCHAR, Revenue FLOAT)

For those records from the products and each product's manufacturer, a bar chart shows the distribution of headquarter and the average of manufacturer , and group by attribute headquarter, order Headquarter in desc order.
SELECT Headquarter, AVG(Manufacturer) FROM Products AS T1 JOIN Manufacturers AS T2 ON T1.Manufacturer = T2.Code GROUP BY Headquarter ORDER BY Headquarter DESC
SELECT "Headquarter", AVG("Manufacturer") FROM "Products" AS "T1" JOIN "Manufacturers" AS "T2" ON "T1"."Manufacturer" = "T2"."Code" GROUP BY "Headquarter" ORDER BY "Headquarter" DESC NULLS LAST