sql server中時間之間的小時差

Question

我正在嘗試使用DATEDIFF(HOUR, FromTime, ToTime)獲取兩個日期之間的DATEDIFF(HOUR, FromTime, ToTime)但是時間是00:00:00。 我得到了負面和錯誤的時間。

下面的代碼：

 select FromTime, ToTime, datepart(HH, FromTime) as fromtimehours, datepart(HH, ToTime) as totimehours, DATEDIFF(HOUR, FromTime, ToTime) as totalhours from table 

Answer 1

如果一個case語句為負值，然后如何正確計算，該如何捕捉：

CASE WHEN DATEDIFF(HOUR, FromTime, ToTime) < 0 
THEN 24 - DATEPART(hour, FromTime) + DATEPART(hour, ToTime)
ELSE DATEDIFF(HOUR, FromTime, ToTime) 
END AS TotalHours