Select COUNT (*) AS Total
From readmodels.Database
Where
    Timestamp >= '2018-01-18' AND
    Timestamp <= '2018-01-19'

Select COUNT(*) as count, DATEPART(year, DATEADD(hour, -6, Timestamp)) as year, DATEPART(month, DATEADD(hour, -6, Timestamp)) as month, DATEPART(day, DATEADD(hour, -6, Timestamp)) as day, DATEPART(hour, DATEADD(hour, -6, Timestamp)) as hour
From readmodels.Database
Where
DATEADD(hour, -6, Timestamp) >= '2018-01-18' AND
DATEADD(hour, -6, Timestamp) <= '2018-01-19'
Group by DATEPART(year, DATEADD(hour, -6, Timestamp)), DATEPART(month, DATEADD(hour, -6, Timestamp)), DATEPART(day, DATEADD(hour, -6, Timestamp)), DATEPART(hour, DATEADD(hour, -6, Timestamp))

SELECT  dateadd(hour, datediff(hour, 0, TimeStamp), 0) as TimeStampHour_CST, Count(*) As Total_Per_Hour
FROM    readmodels.database
WHERE   Timestamp >= '2018-01-17' AND
        Timestamp <= '2018-01-18'
GROUP BY dateadd(hour, datediff(hour, 0, TimeStamp), 0)
ORDER BY dateadd(hour, datediff(hour, 0, TimeStamp), 0);