SQL查询多个日期的最大记录

Question

您好我正在寻找一个SQL查询来根据客户的特定条件选择最大记录。目前的情况如下

Customer            Activity            Date
1                   1                   01/02/2015
1                   1                   02/02/2015
1                   1                   03/02/2015
1                   2                   05/02/2015
1                   2                   07/02/2015
1                   3                   06/02/2015
2                   1                   01/01/2015
2                   2                   05/01/2015
2                   3                   11/01/2015

My Required Resultset应该类似于

Customer        Activity1Maxdate            Activity2Maxdate        Activity3MaxDate
1               03/02/2015                  07/02/2015              06/02/2015
2               01/01/2015                  05/01/2015              11/01/2015

此处的活动限于4或5，因此不需要动态制柱

任何帮助请 干杯

Answer 1

你所问的是一个Pivot表 Sql server有一个用于pivot的关系运算符，你可以阅读它的文档here。

试试这个：

SELECT Customer, 
  [0] As Activity1Maxdate
, [1] As Activity2Maxdate
, [2] As Activity3Maxdate
, [3] As Activity4Maxdate
, [4] As Activity5Maxdate
FROM YourTable
PIVOT
(
MAX(Date)
FOR Activity IN ([0], [1], [2], [3], [4])
) AS PivotTable;