默认 ROW_NUMBER 为一个产品

Question

我创建了一个 table，它将产品信息与主 ID table 结合起来。主 ID 是产品信息通用的外键。因此，购买了多种产品的每个人都将拥有一个共同的主 ID。我想将最早的产品卖给客户 - 所以我使用了 ROW_NUMBER() PARTITION BY.

SELECT PRODUCT_NUM, CO_Cd, PROD_CD, Date,
MASTER_ID,
ROW_NUMBER() OVER (PARTITION BY MASTER_ID ORDER BY Date) ROW_NUM
FROM MyTable
ORDER BY MASTER_ID

但是，我遇到了在同一天购买两种产品的情况。所以 SQL 我想是随机分配 ROW_NUM = 1 给任何产品。在这种情况下，我想默认 ROW_NUM = 1 到 STATIONERY 而不是 PRINTER。我尝试了一个 Case 语句，其中 PARTITION BY MASTER_ID CASE WHEN PROD_CD = 'STATIONERY' THEN 'PA' ORDER BY Date。在这方面需要更多指导。

PRODUCT_NUM	CO_Cd	PROD_CD	MASTER_ID	Date	ROW_NUM
1854	MAWC	PRINTER	10003493039	1/1/2021	1
1567	PREF	STATIONERY	10003493039	1/1/2021	2
2151	PSIA	STATIONERY	10003497290	3/2/2021	1

想要的输出：

PRODUCT_NUM	CO_Cd	PROD_CD	MASTER_ID	Date	ROW_NUM
1854	MAWC	STATIONERY	10003493039	1/1/2021	1
1567	PREF	PRINTER	10003493039	1/1/2021	2
2151	PSIA	STATIONERY	10003497290	3/2/2021	1

Answer 1

您刚刚在 PARTITION BY 中获得了 CASE，它应该在 ORDER BY

中

SELECT
  PRODUCT_NUM,
  CO_Cd,
  PROD_CD,
  Date,
  MASTER_ID,
  ROW_NUMBER() OVER (PARTITION BY MASTER_ID
    ORDER BY Date, CASE WHEN PROD_CD = 'STATIONERY' THEN 1 ELSE 2 END) ROW_NUM
FROM MyTable
ORDER BY MASTER_ID

Answer 2

您可以在 order by 中包含 prod_cd。为此，'STATIONERY' > 'PRINTER' 并且您首先想要它，因此需要进行降序排序：

SELECT PRODUCT_NUM, CO_Cd, PROD_CD, Date, MASTER_ID,
       ROW_NUMBER() OVER (PARTITION BY MASTER_ID ORDER BY Date, PROD_CD DESC) AS ROW_NUM
FROM MyTable
ORDER BY MASTER_ID;

默认 ROW_NUMBER 为一个产品

Default ROW_NUMBER to One Product

sql

tsql

database

sql-server

window-functions