select product.product_id, category.category_id, product.name, category.description
from product , category
inner JOIN category_prodcut ON category.category_id = category_prodcut.category_id
inner JOIN category_prodcut ON product.product_id = category_prodcut.product_id;

select product_id from product;

select p.product_id, c.category_id, p.name, c.description
from category_product cp join
     product p
     on p.product_id = cp.product_id join
     category c
     on c.category_id = cp.category_id;