How to calculate difference between two dates in seconds during business hours for business days SQL Server? - sql

Question

I like to get the difference in seconds between two working days in SQL Server. We have date table contains IsWorkingDay flag, if the end date is null then it should default to getdate(). The workday starts at 8 am and finishes at 4:30 pm.
I have the following query, need help in else part.
#StartDate and #EndDate will not always be on workdays. If #StartDate is on any weekend or Holiday, it should roll up to Next working day at 8:00 am. If #EndDate is on any weekend or Holiday, it should roll up to last working day at 4:30 pm.
CREATE FUNCTION TimeDiffInSeconds
(
#Startdate DATETIME
,#EndDate DATETIME
)
RETURNS INT
AS
BEGIN
DECLARE #WorkSeconds INT = 0;
DECLARE #Reverse BIT;
DECLARE #StartHour FLOAT = 8
DECLARE #EndHour FLOAT = 16.50
IF #Startdate > #EndDate
BEGIN
DECLARE #TempDate DATETIME = #Startdate;
SET #Startdate = #EndDate;
SET #EndDate = #TempDate;
SET #Reverse = 1;
END;
ELSE
SET #Reverse = 0;
IF DATEPART(HH, #StartDate) < #StartHour
SET #StartDate = DATEADD(HOUR, #StartHour, DATEDIFF(DAY, 0, #StartDate));
IF DATEPART(HH, #StartDate) >= #EndHour + 1
SET #StartDate = DATEADD(HOUR, #StartHour + 24, DATEDIFF(DAY, 0, #StartDate));
IF DATEPART(HH, #EndDate) >= #EndHour + 1
SET #EndDate = DATEADD(HOUR, #EndHour, DATEDIFF(DAY, 0, #EndDate));
IF DATEPART(HH, #EndDate) < #StartHour
SET #EndDate = DATEADD(HOUR, #EndHour - 24, DATEDIFF(DAY, 0, #EndDate));
IF #Startdate > #EndDate
RETURN 0;
IF DATEDIFF(DAY, #StartDate, #EndDate) <= 0
BEGIN
IF #Startdate <> (SELECT date_id FROM Final.Date WHERE IsWorkingDay = 0)
SET #WorkSeconds = DATEDIFF(ss, #StartDate, #EndDate); -- Calculate difference
ELSE RETURN 0;
END;
ELSE
--need help
RETURN #WorkSeconds;
END

Answer 1

It can be calculated in a simple way.
If your two parameters are already working days then you can just return their difference in seconds, minus 15.5 hours (16:30 to 08:00) for every day difference (every time the midnight boundary is crossed), minus 8,5 hours (8:00 to 16:30) for every not working day between your two dates.
PS: I have updated the answer, so we now first check if #StartDate and #EndDate are correct working datetimes, and if not then we move them to the correct ones. After that you can apply the previously described calculation for the working time in seconds.
CREATE FUNCTION TimeDiffInSeconds
(
#Startdate datetime,
#EndDate datetime
)
RETURNS INT
AS
BEGIN
set #EndDate = coalesce(#EndDate, getdate());
-- We check that #StartDate is a working datetime, and if not we set it to the next one
if convert(time, #StartDate) < convert(time, '08:00')
begin
set #StartDate = convert(datetime, convert(date, #StartDate)) +
convert(datetime, '08:00')
end
if convert(time, #StartDate) > convert(time, '16:30') or
(select IsWorkingDay
from Final.Date
where date_id = convert(date, #StartDate)) = 0
begin
select top 1 #StartDate = convert(datetime, date_id) +
convert(datetime, '08:00')
from Final.Date
where date_id > #StartDate and IsWorkingDay = 1
order by date_id
end
-- We check that #EndDate is a working datetime, and if not we set it to the last one
if convert(time, #EndDate) > convert(time, '16:30')
begin
set #EndDate = convert(datetime, convert(date, #EndDate)) +
convert(datetime, '16:30')
end
if convert(time, #EndDate) < convert(time, '08:00') or
(select IsWorkingDay
from Final.Date
where date_id = convert(date, #EndDate)) = 0
begin
select top 1 #EndDate = convert(datetime, date_id) +
convert(datetime, '16:30')
from Final.Date
where date_id < #EndDate and IsWorkingDay = 1
order by date_id desc
end
-- We return the working time difference in seconds between #StartDate and #EndDate
RETURN datediff(second, #StartDate, #EndDate) -
((15.5 * datediff(day, #StartDate, #EndDate) * 60 * 60) -
(8.5 * (select count(*)
from Final.Date
where IsWorkingDay = 0 and
(date_id between #StartDate and #EndDate or date_id between #EndDate and #StartDate)
) * 60 * 60));
END
Test online: https://rextester.com/FWR14059