题解 | #返回订单数量总和不小于100的所有订单的订单号#
返回订单数量总和不小于100的所有订单的订单号
http://www.nowcoder.com/practice/ff77e82b59544a15987324e19488aafd
select order_num from OrderItems group by order_num having sum(quantity)>=100 order by order_num
先进行分组,然后使用having进行过滤,然后再进行排序,产生误区的是容易把sum(quantity)放置select后面