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
SELECT prod_name, COUNT(order_num) AS orders FROM Products p LEFT JOIN OrderItems oi ON p.prod_id = oi.prod_id GROUP BY prod_name ORDER BY prod_name ASC; # 要求无实际订单的产品soda也返回,因为MYSQL不支持外连接,所以用左连接 # 左连接结果如下 # a0013 coffee a0013 a1121 # a0003 cola a0003 a5 # a0003 cola a0003 a19 # … # 聚合计数即可