三种方法

#方法一
select cust_id, order_date
from Orders,
(select order_num
from OrderItems
where prod_id="BR01") t
where t.order_num = Orders.order_num
order by order_date;
#方法二
select cust_id,order_date
from Orders 
where order_num in 
(select order_num
from OrderItems
where prod_id="BR01")
order by order_date;
#方法三
select cust_id,order_date
from Orders o join OrderItems oi on o.order_num=oi.order_num
where prod_id="BR01"
order by order_date;