For each phone, show its names and total number of stocks.
create table phone_market (num_of_stock integer, phone_id varchar, PRIMARY KEY (num_of_stock)); create table phone (name varchar, phone_id varchar, PRIMARY KEY (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