獲取一個datediff結果的總和

Question

我有一個SQL語句（MS SQL Server 2005），可以簡單計算幾條記錄中的日期差異。我想要返回DATEDIFF的總數/總數。

SELECT  (DATEDIFF(day, StartDate, EndDate)+1) AS myTotal 
FROM   myTable 
WHERE  (Reason = '77000005471247') 

如何從myTotal獲取SUM？這就是我想要回報的一切。

在此先感謝

Answer 1

如果包括其他列，你需要還包括GROUP BY子句

SELECT  AnotherColumn, SUM(DATEDIFF(day, StartDate, EndDate)+1) AS myTotal 
FROM   myTable 
WHERE  (Reason = '77000005471247') 
GROUP BY AnotherColumn 

Answer 2

使用SUM合計：

SELECT  SUM(DATEDIFF(day, StartDate, EndDate)+1) AS myTotal 
FROM   myTable 
WHERE  (Reason = '77000005471247')