之前有一题说要用outter join

其实left和right join都属于outer join

且根据题目的描述，这里并不适合使用全连接（使用左连接，结果如下）

select Vendors.vend_id as vend_id, count(Products.prod_id) as prod_id
from Vendors 
left join Products
on Vendors.vend_id = Products.vend_id
group by Vendors.vend_id
order by Vendors.vend_id