CREATE TABLE Addresses (city VARCHAR2, address_id VARCHAR2)
CREATE TABLE Staff (staff_address_id VARCHAR2)

Which city lives most of staffs? List the city name and number of staffs.
SELECT T1.city, COUNT(*) FROM Addresses AS T1 JOIN Staff AS T2 ON T1.address_id = T2.staff_address_id GROUP BY T1.city ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T1"."city", COUNT(*) FROM "Addresses" "T1" JOIN "Staff" "T2" ON "T1"."address_id" = "T2"."staff_address_id" GROUP BY "T1"."city" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY