Calculate business hours between two dates

Question

How can I calculate business hours between two dates? For example we have two dates; 01/01/2010 15:00 and 04/01/2010 12:00 And we have working hours 09:00 to 17:00 in weekda

Answer 1

The first step would be to calculate working days, as shown in the script below:

DECLARE @TotalWorkDays INT, @TotalTimeDiff DECIMAL(18, 2), @DateFrom DATETIME, @DateTo DATETIME;
SET @DateFrom = '2017-06-05 11:19:11.287';
SET @DateTo = '2017-06-07 09:53:14.750';

SET @TotalWorkDays = DATEDIFF(DAY, @DateFrom, @DateTo)
    -(DATEDIFF(WEEK, @DateFrom, @DateTo) * 2)
   -CASE
                                    WHEN DATENAME(WEEKDAY, @DateFrom) = 'Sunday'
                                    THEN 1
                                    ELSE 0
                                END+CASE
                                        WHEN DATENAME(WEEKDAY, @DateTo) = 'Saturday'
                                        THEN 1
                                        ELSE 0
                                    END;

The second step involves getting a difference in seconds between the two dates and converting that difference into hours by dividing by 3600.0 as shown in this following script:

SET @TotalTimeDiff =
(
    SELECT DATEDIFF(SECOND,
                   (
                       SELECT CONVERT(TIME, @DateFrom)
                   ),
                   (
                       SELECT CONVERT(TIME, @DateTo)
                   )) / 3600.0
);

The last part involves multiplying the output the first step above by 24 (total number of hours in a day) and then later adding that to the output of the second step:

SELECT(@TotalWorkDays * 24.00) + @TotalTimeDiff;

Finally, the complete script that can be used to create a user defined function for calculating working hours is shown below:

CREATE FUNCTION [dbo].[fn_GetTotalWorkingHours]
(
    @DateFrom Datetime,
    @DateTo Datetime
)
RETURNS DECIMAL(18,2)
AS
BEGIN

DECLARE @TotalWorkDays INT, @TotalTimeDiff DECIMAL(18, 2)

SET @TotalWorkDays = DATEDIFF(DAY, @DateFrom, @DateTo)
    -(DATEDIFF(WEEK, @DateFrom, @DateTo) * 2)
   -CASE
                                    WHEN DATENAME(WEEKDAY, @DateFrom) = 'Sunday'
                                    THEN 1
                                    ELSE 0
                                END+CASE
                                        WHEN DATENAME(WEEKDAY, @DateTo) = 'Saturday'
                                        THEN 1
                                        ELSE 0
                                    END;
SET @TotalTimeDiff =
(
    SELECT DATEDIFF(SECOND,
                   (
                       SELECT CONVERT(TIME, @DateFrom)
                   ),
                   (
                       SELECT CONVERT(TIME, @DateTo)
                   )) / 3600.0
);

RETURN  (SELECT(@TotalWorkDays * 24.00) + @TotalTimeDiff)

END
GO

The complete method is descibed in this article: https://www.sqlshack.com/how-to-calculate-work-days-and-hours-in-sql-server/