SQL之子查询（2）

案例1：

表OrderItems代表订单商品信息表，prod_id为产品id；Orders表代表订单表有cust_id代表顾客id和订单日期order_date

OrderItems表

prod_id	order_num
BR01	a0001
BR01	a0002
BR02	a0003
BR02	a0013

Orders表

order_num	cust_id	order_date
a0001	cust10	2022-01-01 00:00:00
a0002	cust1	2022-01-01 00:01:00
a0003	cust1	2022-01-02 00:00:00
a0013	cust2	2022-01-01 00:20:00

【问题】

编写 SQL 语句，使用子查询来确定哪些订单（在 OrderItems 中）购买了 prod_id 为 "BR01" 的产品，然后从 Orders 表中返回每个产品对应的顾客 ID（cust_id）和订单日期（order_date），按订购日期对结果进行升序排序。

提示：这一次使用联结和简单的等联结语法。

--t1:
select
  cust_id,
  order_date
from
  Orders,
  (
    select
      order_num
    from
      OrderItems
    where
      prod_id = 'BR01'
  ) t
where
  Orders.order_num = t.order_num
order by
  order_date 


--t2:
select
  cust_id,
  order_date
from
  Orders
where
  order_num in (
    select
      order_num
    from
      OrderItems
    where
      prod_id = 'BR01'
  )
order by
  order_date 

--t3:
select
  cust_id,
  order_date
from
  Orders a
  left join OrderItems b on a.order_num = b.order_num
where
  prod_id = 'BR01'
order by
  order_date

【示例结果】

返回顾客id cust_id和定单日期order_date

cust_id	order_date
cust10	2022-01-01 00:00:00
cust1	2022-01-01 00:01:00