Question

我需要列出客户表中的列，第一个订单的日期和最后一个的所有数据，客户和订单表之间的1：N关系。我正在使用Oracle 10g。

最好的方法是什么？

TABLE CUSTOMER
---------------
id              NUMBER
name            VARCHAR2(200)
subscribe_date  DATE


TABLE ORDER
---------------
id              NUMBER
id_order        NUMBER
purchase_date   DATE
purchase_value  NUMBER

Answer 1

以下是一种方法，使用row_number函数，一个连接和聚合：

select c.*,
       min(o.purchase_date) as FirstPurchaseDate, 
       min(case when seqnum = 1 then o.id_order end) as Last_IdOrder,
       min(case when seqnum = 1 then o.purchase_date end) as Last_PurchaseDate,
       min(case when seqnum = 1 then o.purchase_value end) as Last_PurchaseValue
from Customer c join
     (select o.*,
             row_number() over (partition by o.id order by purchase_date desc) as seqnum
      from orders o
     ) o
     on c.customer_id = o.order_id
group by c.customer_id, c.name, c.subscribe_date

Answer 2

如何将customer表加入orders表并不明显（order是Oracle中的保留字，因此您的表不能命名为order）。如果我们假设id_order中的orders加入id中的customer

SELECT c.id customer_id,
       c.name name,
       c.subscribe_date,
       o.first_purchase_date,
       o.id last_order_id,
       o.purchase_date last_order_purchase_date,
       o.purchase_value last_order_purchase_value
  FROM customer c
       JOIN (SELECT o.*,
                    min(o.purchase_date) over (partition by id_order) first_purchase_date,
                    rank() over (partition by id_order order by purchase_date desc) rnk
               FROM orders o) o ON (c.id = o.id_order)
 WHERE rnk = 1

Answer 3

我对你的字段名称感到困惑，但我会假设ORDER.id是CUSTOMER表中的id。

最早的订单日期很简单。

select CUSTOMER.*, min(ORDER.purchase_date)
from CUSTOMER
  inner join ORDER on CUSTOMER.id = ORDER.id
group by CUSTOMER.*

要获取最后的订单数据，请再次将其加入ORDER表。

select CUSTOMER.*, min(ORD_FIRST.purchase_date), ORD_LAST.*
from CUSTOMER
  inner join ORDER ORD_FIRST on CUSTOMER.id = ORD_FIRST.id
  inner join ORDER ORD_LAST on CUSTOMER.id = ORD_LAST.id
group by CUSTOMER.*, ORD_LAST.*
having ORD_LAST.purchase_date = max(ORD_FIRST.purchase_date)

Answer 4

也许是这样的假设ID表中的Order字段实际上是Customer ID：

SELECT C.*, O1.*, O2.purchase_Date as FirstPurchaseDate
FROM Customer C
LEFT JOIN 
(
  SELECT Max(purchase_date) as pdate, id
  FROM Orders
  GROUP BY id
) MaxPurchaseOrder 
  ON C.Id = MaxPurchaseOrder.Id
LEFT JOIN Orders O1 
  ON MaxPurchaseOrder.pdate = O1.purchase_date 
  AND MaxPurchaseOrder.id = O1.id
LEFT JOIN 
(
  SELECT Min(purchase_date) as pdate, id
  FROM Orders
  GROUP BY id
) MinPurchaseOrder 
  ON C.Id = MinPurchaseOrder.Id
LEFT JOIN Orders O2 
  ON MinPurchaseOrder.pdate = O2.purchase_date 
  AND MinPurchaseOrder.id = O2.id

sql fiddle。

Oracle SQL中的最后一个订单项

4 个答案: