题解 | #返回产品名称和与之相关的订单号#

#【问题】
使用 OUTER JOIN 联结 Products 表和 OrderItems 表，返回产品名称（prod_name）和与之相关的订单号（order_num）的列表，并按照产品名称升序排序
select
    prod_name,
    order_num
from
    Products a
    left join OrderItems b on a.prod_id = b.prod_id
union
select
    prod_name,
    order_num
from
    Products c
    right join OrderItems d on c.prod_id = d.prod_id
where
    c.prod_id is null
order by
    prod_name;