题解 | #确定哪些订单购买了 prod_id 为 BR01

select cust_id,order_date from Orders a,OrderItems b
where b.prod_id='BR01' and a.order_num=b.order_num
order by order_date

select

cust_id,

order_date

from

Orders t

inner join OrderItems t1 on t.order_num = t1.order_num

where

prod_id = "BR01"

order by

order_date

感觉应该直接join 我觉得还可以子查询 join后直接where就行，语法更简单

select cust_id,order_date

from Orders

where order_num in (select order_num

                    from OrderItems

                    where prod_id="BR01")

order by order_date

子查询的答案