How to average/sum data in a day in SQL Server 2005

Question

I\'m trying to average data in SQL Server 2005 in a day. Here is what my database look like this if I use simple query as

SELECT timestamp, FEED
FROM ROASTE         


        

Answer 1

7:40am is 460 minutes after 00:00

7:40pm is 1180 minutes after 00:00

midnigth is 1440 minutes after 00:00

And DATEPART(hh, SomeDate)*60 + DATEPART(mi, SomeDate) gives you the amount of minutes after 00:00 for a given SomeDate

So, you could use:

SELECT
    AVG(Temperature) As Dayshift
FROM Drye_data
WHERE DATEPART(hh, TimeStamp)*60 + DATEPART(mi, TimeStamp) BETWEEN 460 AND 1180
      AND @SelectedDate = CAST(FLOOR(CAST(TimeStamp AS FLOAT)) AS DATETIME)

and for the Nightshift:

    SELECT
    AVG(Temperature) As Nigthshift
FROM Drye_data
WHERE (
        (DATEPART(hh, TimeStamp)*60 + DATEPART(mi, TimeStamp) BETWEEN 0 AND 460)
        AND @SelectedDate = DATEADD(dd, 1, CAST(FLOOR(CAST(TimeStamp AS FLOAT)) AS DATETIME))
      )
      OR 
      (
         (DATEPART(hh, TimeStamp)*60 + DATEPART(mi, TimeStamp) BETWEEN 1180 AND 1440) AND @SelectedDate = CAST(FLOOR(CAST(TimeStamp AS FLOAT)) AS DATETIME)
      )