CREATE TABLE Manufacturers (Code NUMBER, Name VARCHAR2, Headquarter VARCHAR2, Founder VARCHAR2, Revenue FLOAT)
CREATE TABLE Products (Code NUMBER, Name VARCHAR2, Price NUMBER, Manufacturer NUMBER)

Please tell the revenues of the companies with the highest revenues in each headquarter city.
SELECT Headquarter, MAX(Revenue) FROM Manufacturers GROUP BY Headquarter
SELECT "Headquarter", MAX("Revenue") FROM "Manufacturers" GROUP BY "Headquarter"