题解 | #返回每个订单号各有多少行数#
返回每个订单号各有多少行数
http://www.nowcoder.com/practice/cf1f8d4a514d455aa0468718fb411f41
select order_num,count(order_num) order_lines from OrderItems group by order_num order by order_lines
#返回每个订单号各有多少行数# 利用group by 进行分组,对分组数据进行统计,然后进行排序