对于每个保修索赔，如何进行有条件的最大退货以从客户那里退回最后一次购买？

Question

您好，我有一个如下所示的数据表

OrderID	Date	Product Name	CustomerID
476070	February 24,2021	WARRANTY CLAIM	ABC123
476069	February 22,2021	PRODUCT C	ABC123
476068	February 10,2021	WARRANTY CLAIM	ABC123
476067	February 1,2021	WARRANTY CLAIM	ABC123
476064	January 23,2021	PRODUCT B	ABC123
476051	January 10,2021	WARRANTY CLAIM	ABC123
475023	January 1 , 2021	PRODUCT A	ABC123

我想要实现的是对于每个保修索赔，我想获得该客户的最后一次产品购买。

所以意思就是我想要达到的输出是这样的

OrderID	Date	Product Name	CustomerID	LASTPRODUCTPURCHASE
476070	February 24,2021	WARRANTY CLAIM	ABC123	PRODUCT C
476069	February 22,2021	PRODUCT C	ABC123	NULL
476068	February 10,2021	WARRANTY CLAIM	ABC123	PRODUCT B
476067	February 1,2021	WARRANTY CLAIM	ABC123	PRODUCT B
476064	January 23,2021	PRODUCT B	ABC123	NULL
476051	January 10,2021	WARRANTY CLAIM	ABC123	PRODUCT A
475023	January 1 , 2021	PRODUCT A	ABC123	NULL

我已经尝试过 LAG 和 MAXIF，但它会返回该特定客户的先前订单或最新订单。我需要该客户的LAST产品购买，并且仅适用于保修索赔订单。

我正在为 CTE 解决方案获取此输出

这是我运行的查询：

WITH cte AS (
    SELECT *, MAX(CASE WHEN productName <> 'Warranty Service' OR productName <> 'Warranty Collect' OR productName <> 'Warranty Inspection' OR productName <> 'Delivery' THEN id END) OVER
                  (PARTITION BY vpn ORDER BY ordercompleted_at) MaxOrderID
    FROM baterikudatawarehouse.bateriku_production.BaterikuOrderTrafficJune2020
    where orderStatus = 'completed' and vpn = 'QMY70' order by ordercompleted_at DESC
)

SELECT t1.id ,t1.ordercompleted_at, t1.productName, t1.vpn,
       CASE WHEN t1.productName = 'Warranty Service' OR t1.productName = 'Warranty Collect' OR t1.productName = 'Delivery' OR t1.productName = 'Warranty Inspection'
            THEN t2.productName END AS LASTPRODUCTPURCHASE
FROM cte t1

INNER JOIN baterikudatawarehouse.bateriku_production.BaterikuOrderTrafficJune2020 t2
    ON t2.vpn = t1.vpn AND
       t2.id = t1.MaxOrderId ORDER BY t1.ordercompleted_at DESC;

Answer 1

这是使用lead 的另一种方法：

select orderid,Date,productname,customerid,
       case when productname = 'WARRANTY CLAIM' then
       max(lastpn)over(partition by customerid order by orderid) else null end as LASTPRODUCTPURCHASE 
       from (
             select tb.*, 
             case when lead(productname)over(partition by customerid order by OrderID desc) = 'WARRANTY CLAIM' then null 
             else lead(productname)over(partition by customerid order by OrderID desc) end as lastpn
             from tb
            ) a

这里是db<>fiddle，包括@Tim Biegeleisen 答案，如果允许 CTE，IMO 会更好地选择。
我还在 dbfiddle 中添加了更多带有示例数据的行以便更好地检查。

Answer 2

一种方法，首先在每个时间点找到每个客户的最新订单：

WITH cte AS (
    SELECT *, MAX(CASE WHEN ProductName <> 'WARRANTY CLAIM' THEN OrderID END) OVER
                  (PARTITION BY CustomerID ORDER BY Date) MaxOrderID
    FROM yourTable
)

SELECT t1.OrderID, t1.Date, t1.ProductName, t1.CustomerID,
       CASE WHEN t1.ProductName = 'Warranty Claim'
            THEN t2.ProductName END AS LASTPRODUCTPURCHASE
FROM cte t1
INNER JOIN yourTable t2
    ON t2.CustomerID = t1.CustomerID AND
       t2.OrderID = t1.MaxOrderId;

请注意，返回原始表的连接会从最近的非保修事务中提取最新的产品名称。