题解 | #返回产品名称和每一项产品的总订单数#
返回产品名称和每一项产品的总订单数
https://www.nowcoder.com/practice/1c64fd9048364a58a8ffa541720359a4
count(列名) 里的行如果有空值null,就会记为0。
select prod_name,count(order_num) orders from Products left join OrderItems on OrderItems.prod_id=Products.prod_id group by prod_name order by prod_name asc