Returning only one row for an aggregate function per a time period and user

Question

I'm using SQL Server 2008.

I have table constructed the following way:

Date (datetime)
TimeIn (datetime) 
TimeOut (datetime)
UserReference (nvarchar)
LocationID

My desired results are: For every hour between hour 7 (7am) and hour 18 (6pm) I want to know the user who had the highest (TimeIn - TimeOut) for every location. -last condition is optional-

So I've got an aggregated function which calculates the datediff in seconds between TimeOut and TimeIn aliased as Total

I want my results to look a bit like this:

Hour 7 | K1345 | 50 | Place #5
Hour 7 | K3456 | 10 | Place #4
Hour 8 | K3333 | 5  | Place #5

etc.

What I've tried so far:

A CTE using the ROW_NUMBER() function, partitioning by my aggregated column and ordering by it. This only returns one row.

A CTE where I do all my aggregations (including datepart(hour,date)) and use the max aggregation to get the highest total time in my outer query.

I know I have to do it with a CTE somehow, I'm just not exactly sure how to join the cte and my outer query.

Am I on the right track using a ROW_NUMBER() or Rank()?

Queries I've tried:

WITH cte as 
(
SELECT * ,
       rn = ROW_NUMBER() over (partition by datediff(second, [TimeIn], [TimeOut])order by datediff(second, [TimeIn], [TimeOut]) desc)
FROM TimeTable  (nolock)
where DateCreated > '20131023 00:00:00' and DateCreated < '20131023 23:59:00'    
)
SELECT  datepart(hour,cte.DateCreated) as hour,cte.UserReference,(datediff(second, [TimeIn], [TimeOut])) as [Response Time],LocationID
from cte
where cte.rn = 1
and  DATEPART(hh,datecreated) >= 7 and DATEPART(hh,datecreated) <= 18
order by hour asc

This only returns a few rows

something else I've tried:

with cte as 
(
SELECT Datecreated as Date,
       UserReference as [User],
       datediff(second, [TimeIn], [TimeOut]) as Time,
       LocationID as Location
FROM TimeTable
WHERE datecreated... --daterange
)
SELECT DATEPART(HOUR,date), cte.[User], MAX(Time), Location
FROM cte
WHERE  DATEPART(hh,datecreated) >= 7 and DATEPART(hh,datecreated) <= 18
GROUP BY DATEPART(HOUR,date), cte.[User], Location

Row of sample data

Date                    UserRef TimeIn                  TimeOut          locationid
2013-10-23 06:26:12.783 KF34334 2013-10-23 06:27:07.000 2013-10-23 06:27:08.000 10329

Answer 1

I hope this will help

   WITH TotalTime AS (
        SELECT  
            CAST(DateCreated AS DATE) as [date] 
            ,DATEPART(hour,DateCreated) AS [hour]
            ,SUM(DATEDIFF(second,TimeIn,TimeOut)) AS Total
            ,UserReference 
            ,locationid
        FROM    TimeTable
        GROUP BY UserReference,locationid,CAST(DateCreated AS DATE),DATEPART(hour,DateCreated) 
        HAVING DATEPART(hh,DateCreated) >= 7 and DATEPART(hh,DateCreated) <= 18
    )
    , rn AS (
        SELECT *, ROW_NUMBER() OVER (PARTITION BY [date],[hour],locationid ORDER BY Total DESC) AS row_num
        FROM TotalTime
    )
    SELECT *
    FROM rn 
    WHERE row_num = 1