CREATE TABLE manufacturers (Headquarter VARCHAR2, code VARCHAR2)
CREATE TABLE products (name VARCHAR2, Manufacturer VARCHAR2)

Find the number of different products that are produced by companies at different headquarter cities.
SELECT COUNT(DISTINCT T1.name), T2.Headquarter FROM products AS T1 JOIN manufacturers AS T2 ON T1.Manufacturer = T2.code GROUP BY T2.Headquarter
SELECT COUNT(DISTINCT "T1"."name"), "T2"."Headquarter" FROM "products" "T1" JOIN "manufacturers" "T2" ON "T1"."Manufacturer" = "T2"."code" GROUP BY "T2"."Headquarter"