Question

我有一个查询，它给了我所有客户和他们的最后三个订单日期。

EX：

CustomerId DateOrdered
167 2006-09-16 01:25:38.060
167 2006-09-21 13:11:53.530
171 2006-08-31 15:19:22.543
171 2006-09-01 13:30:54.013
171 2006-09-01 13:34:36.483
178 2006-09-04 11:36:19.983
186 2006-09-05 12:50:27.153
186 2006-09-05 12:51:08.513

我想知道是否有办法让我将其转移到这样显示：

[CustomerId]    [Most Recent] [Middle] [Oldest]
'167'   '2006-09-21 13:11:53.530'   '2006-09-16 01:25:38.060'   'NULL'
'171'    '2006-09-01 13:34:36.483'   '2006-09-01 13:30:54.013'   '2006-08-31 15:19:22.543'
'178'   '2006-09-04 11:36:19.983'   NULL    NULL
'186'   '2006-09-05 12:51:08.513'   '2006-09-05 12:50:27.153'   NULL

Answer 1

;WITH YourQuery As
(
SELECT CustomerId, DateOrdered,
ROW_NUMBER() OVER (PARTITION BY CustomerId ORDER BY DateOrdered DESC) AS RN
FROM Orders
)
select [CustomerId],
MAX(CASE WHEN RN=1 THEN DateOrdered END) AS  [Most Recent] ,
MAX(CASE WHEN RN=2 THEN DateOrdered END) AS  [Middle] ,
MAX(CASE WHEN RN=3 THEN DateOrdered END) AS  [Oldest] 
FROM YourQuery
WHERE RN<=3
GROUP BY [CustomerId]

Answer 2

警告：未经测试

我认为你正在寻找这样的东西。特定的连接和where子句可能需要一些工作，但基本上你只是将表连接回来以便每次都获得一个日期。

SELECT C.CUSTOMERID, C.DATEORDERED, C2.DATEORDERED, C3.DATEORDERED
FROM CUSTOMER C
INNER JOIN CUSTOMER C2 ON C.CUSTOMERID = C2.CUSTOMERID
INNER JOIN CUSTOMER C3 ON C.CUSTOMERID = C3.CUSTOMERID
WHERE C.DATEORDERED = MAX(C.DATEORDERED)
AND C2.DATEORDERED < C.DATEORDERED AND 
    (C3.DATEORDERED IS NULL OR C2.DATEORDERED >     C3.DATEORDERED)

有没有办法透过客户ID和他们最近的订单日期？

2 个答案: