CREATE TABLE phone_market (Num_of_stock INT, Phone_ID VARCHAR)
CREATE TABLE phone (Name VARCHAR, Phone_ID VARCHAR)

For each phone, show its names and total number of stocks.
SELECT T2.Name, SUM(T1.Num_of_stock) FROM phone_market AS T1 JOIN phone AS T2 ON T1.Phone_ID = T2.Phone_ID GROUP BY T2.Name
SELECT "T2"."Name", SUM("T1"."Num_of_stock") FROM "phone_market" AS "T1" JOIN "phone" AS "T2" ON "T1"."Phone_ID" = "T2"."Phone_ID" GROUP BY "T2"."Name"