获取一个datediff结果的总和

Question

我有一个SQL语句（MS SQL Server 2005），可以简单计算几条记录中的日期差异。我想要返回DATEDIFF的总数/总数。

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

如何从myTotal获取SUM？这就是我想要回报的一切。

在此先感谢

Answer 1

如果包括其他列，你需要还包括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合计：

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