SQL Server PIVOT也许? [英] SQL Server PIVOT perhaps?

问题描述

SELECT Name1, Name2, Value FROM mytable给我以下结果集:

Name1 Name2 Value
A     P1     1
A     P2     1
A     P3     2
B     P1     3
B     P2     1
B     P4     1

我如何将其翻译为:

       A     B
P1     1     4
P2     1     1
P3     2     null
P4     null  1

谢谢

推荐答案

您可以使用

You can use a PIVOT clause. Your query could be something like this:

WITH Source as (
    SELECT Name1, Name2, [Value]
    FROM mytable 
)

SELECT Name2, CASE WHEN A IS NOT NULL THEN A ELSE 'your string' END As A
, CASE WHEN B IS NOT NULL THEN B ELSE 'your string' END As B
FROM (
        SELECT Name2, Name1, [Value]
        FROM Source
) s
PIVOT 
(
    MAX([Value]) FOR Name1 IN (A, B) -- any other Name1 would go here
) p

使用上面的示例数据，我的结果是

using your sample data above, my results were

P1  1           3
P2  1           1
P3  2           your string
P4  your string 1

由于列数未知，您将需要使用动态SQL，因此在SO上有一些关于PIVOT的答案.

Since you have an unknown number of columns, you will need to look at using dynamic SQL and there are several answers here on SO about that with PIVOT.

有关未知列数的SQL Server 2005数据透视

数据透视表和连接列

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