题解 | #确定哪些订单购买了 p#

1、子查询

select cust_id, order_date from Orders
where order_num in(
    select order_num from OrderItems 
    where prod_id = "BR01"
)
order by order_date

2、关联查询

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