Question

我有一张这样的表：

Acct    MasterAcct 
------- -------------
123     M01  
123     M02  
234     M03  
345     M04  
456     M05  
456     M06  
456     M07

我想将MasterAcct列分为三列（Master1，Master2，Master3）。一个帐户最多可以有三个与之关联的主帐户。上一个表的示例输出在一行上有＃456帐户，然后在Master1，Master2和Master3中有三个主帐号。有人可以帮忙吗？

Answer 1

您可以将PIVOT与ROW_NUMBER()排名功能结合使用。

SELECT Acct, [1] as [Master1], [2] as [Master2], [3] as [Master3]
FROM
  (
      SELECT Acct, 
            MasterAcct, 
            ROW_NUMBER() OVER(PARTITION BY acct ORDER BY MasterAcct) as mid
      FROM tbl
   ) as t
PIVOT
(
   MIN(MasterAcct)
   FOR mid IN ([1], [2], [3])
) as p

<强> SQL FIDDLE DEMO

您可以在不使用PIVOT的情况下获得相同的结果。以下查询很容易理解。

SELECT
    Acct,
    MAX(CASE WHEN mid=1 THEN MasterAcct END) as [Master1],
    MAX(CASE WHEN mid=2 THEN MasterAcct END) as [Master2],
    MAX(CASE WHEN mid=3 THEN MasterAcct END) as [Master3]
FROM
   (
      SELECT Acct, 
            MasterAcct, 
            ROW_NUMBER() OVER(PARTITION BY acct ORDER BY MasterAcct) as mid
      FROM tbl
   ) t
GROUP BY Acct

<强> SQL FIDDLE DEMO

根据现有列中的数据创建列，存在重复数据

1 个答案: