list the names of all of the products.
select name from products
which products are produced by the company Creative Labs?
select t1.name from products as t1 join manufacturers as t2 on t1.manufacturer = t2.code where t2.name = 'Creative Labs'
among them, find the products that Sony also produces.
select t1.name from products as t1 join manufacturers as t2 on t1.manufacturer = t2.code where t2.name = 'Creative Labs' intersect select t1.name from products as t1 join manufacturers as t2 on t1.manufacturer = t2.code where t2.name = 'Sony'