SQL - 樞軸/ Unpivot？

Question

我在SQL Server 2008中的表格式如下（簡化格式）：

Date Miles Cost

我想得到這樣

  Previous Week  Current Week Variance 
Miles   

Cost

結果我怎樣才能做到這一點？我是否需要pivot/unpivot或者什麼是實現這個目標的最簡單和最有效的方法。謝謝。

Answer 1

SELECT 'Miles' AS Type, SUM(CASE WHEN date = lastweek THEN miles ELSE 0 END) as lastweek 
, SUM(CASE WHEN date = thisweek THEN miles ELSE 0 END) as thisweek 
SUM(CASE WHEN date = lastweek THEN miles ELSE 0 END) - SUM(CASE WHEN date = thisweek THEN miles ELSE 0 END) as variance 
FROM yourtable 
UNION 
SELECT 'Cost' AS Type, SUM(CASE WHEN date = lastweek THEN cost ELSE 0 END) as lastweek 
, SUM(CASE WHEN date = thisweek THEN cost ELSE 0 END) as thisweek 
SUM(CASE WHEN date = lastweek THEN cost ELSE 0 END) - SUM(CASE WHEN date = thisweek THEN cost ELSE 0 END) as variance 
FROM yourtable 

這是不是100％正確，但語法應該是正確的，應該讓你很接近好像你正在尋找