Question

我在这里有一个基本的PIVOT问题，可能不会给你的大师带来任何麻烦：

我得到了这个正常运行的SQL：

SELECT order_year, SUM(amount) AS Amount 
FROM dbo.mytable
GROUP BY order_year;

这会返回声音：

2010 7000000
2007 8051222
2008 7099057
2009 13088790

现在我想使用与此MSDN文章中描述的相同原则来转动表：http://msdn.microsoft.com/en-us/library/ms177410.aspx

我试过了：

SELECT 'Amount' AS Total_Amount_Sorted_By_Order_Year, 
[0], [1], [2], [3], [4]
FROM
(SELECT order_year, amount 
    FROM dbo.mytable ) AS SourceTable
PIVOT
(
SUM(amount)
FOR order_year IN ([0], [1], [2], [3], [4])
) AS PivotTable;

但这会返回一堆NULL！：（

Amount NULL NULL NULL NULL NULL

我做错了什么？任何帮助表示赞赏！

谢谢！

Answer 1

谢谢巴里。我误读了MSDN上的文档，并认为[0]，[1]等标签中的pivot-columns的枚举...（！）

用实际年份取代它们使聚合工作正常！

SELECT 'Amount' AS Total_Amount_Sorted_By_Order_Year,  
[2007], [2008], [2009], [2010]
FROM 
(SELECT order_year, amount  
    FROM dbo.mytable ) AS SourceTable 
PIVOT 
( 
SUM(amount) 
FOR order_year IN ([2007], [2008], [2009], [2010]) 
) AS PivotTable;

PIVOT基础知识：为什么我的聚合返回NULL？

1 个答案: