题解 | #返回订单数量总和不小于100的所有订单的订单号#

select order_num
from OrderItems
group by order_num
having sum(quantity) >= 100
order by order_num

使用having条件语句，附加SQL执行的顺序：

From..... → where条件语句 → group by 分组 → 聚合函数计算 → having条件语句 → order by 排序语句