How can I calculate the number of work days between two dates in SQL Server?
Monday to Friday and it must be T-SQL.
I know this is an old question but I needed a formula for workdays excluding the start date since I have several items and need the days to accumulate correctly.
None of the non-iterative answers worked for me.
I used a defintion like
Number of times midnight to monday, tuesday, wednesday, thursday and friday is passed
(others might count midnight to saturday instead of monday)
I ended up with this formula
SELECT DATEDIFF(day, @StartDate, @EndDate) /* all midnights passed */
- DATEDIFF(week, @StartDate, @EndDate) /* remove sunday midnights */
- DATEDIFF(week, DATEADD(day, 1, @StartDate), DATEADD(day, 1, @EndDate)) /* remove saturday midnights */
One approach is to 'walk the dates' from start to finish in conjunction with a case expression which checks if the day is not a Saturday or a Sunday and flagging it(1 for weekday, 0 for weekend). And in the end just sum flags(it would be equal to the count of 1-flags as the other flag is 0) to give you the number of weekdays.
You can use a GetNums(startNumber,endNumber) type of utility function which generates a series of numbers for 'looping' from start date to end date. Refer http://tsql.solidq.com/SourceCodes/GetNums.txt for an implementation. The logic can also be extended to cater for holidays(say if you have a holidays table)
declare @date1 as datetime = '19900101'
declare @date2 as datetime = '19900120'
select sum(case when DATENAME(DW,currentDate) not in ('Saturday', 'Sunday') then 1 else 0 end) as noOfWorkDays
from dbo.GetNums(0,DATEDIFF(day,@date1, @date2)-1) as Num
cross apply (select DATEADD(day,n,@date1)) as Dates(currentDate)
DECLARE @TotalDays INT,@WorkDays INT
DECLARE @ReducedDayswithEndDate INT
DECLARE @WeekPart INT
DECLARE @DatePart INT
SET @TotalDays= DATEDIFF(day, @StartDate, @EndDate) +1
SELECT @ReducedDayswithEndDate = CASE DATENAME(weekday, @EndDate)
WHEN 'Saturday' THEN 1
WHEN 'Sunday' THEN 2
ELSE 0 END
SET @TotalDays=@TotalDays-@ReducedDayswithEndDate
SET @WeekPart=@TotalDays/7;
SET @DatePart=@TotalDays%7;
SET @WorkDays=(@WeekPart*5)+@DatePart
RETURN @WorkDays
CREATE FUNCTION x
(
@StartDate DATETIME,
@EndDate DATETIME
)
RETURNS INT
AS
BEGIN
DECLARE @Teller INT
SET @StartDate = DATEADD(dd,1,@StartDate)
SET @Teller = 0
IF DATEDIFF(dd,@StartDate,@EndDate) <= 0
BEGIN
SET @Teller = 0
END
ELSE
BEGIN
WHILE
DATEDIFF(dd,@StartDate,@EndDate) >= 0
BEGIN
IF DATEPART(dw,@StartDate) < 6
BEGIN
SET @Teller = @Teller + 1
END
SET @StartDate = DATEADD(dd,1,@StartDate)
END
END
RETURN @Teller
END
As with DATEDIFF, I do not consider the end date to be part of the interval. The number of (for example) Sundays between @StartDate and @EndDate is the number of Sundays between an "initial" Monday and the @EndDate minus the number of Sundays between this "initial" Monday and the @StartDate. Knowing this, we can calculate the number of workdays as follows:
DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME
SET @StartDate = '2018/01/01'
SET @EndDate = '2019/01/01'
SELECT DATEDIFF(Day, @StartDate, @EndDate) -- Total Days
- (DATEDIFF(Day, 0, @EndDate)/7 - DATEDIFF(Day, 0, @StartDate)/7) -- Sundays
- (DATEDIFF(Day, -1, @EndDate)/7 - DATEDIFF(Day, -1, @StartDate)/7) -- Saturdays
Best regards!
None of the functions above work for the same week or deal with holidays. I wrote this:
create FUNCTION [dbo].[ShiftHolidayToWorkday](@date date)
RETURNS date
AS
BEGIN
IF DATENAME( dw, @Date ) = 'Saturday'
SET @Date = DATEADD(day, - 1, @Date)
ELSE IF DATENAME( dw, @Date ) = 'Sunday'
SET @Date = DATEADD(day, 1, @Date)
RETURN @date
END
GO
create FUNCTION [dbo].[GetHoliday](@date date)
RETURNS varchar(50)
AS
BEGIN
declare @s varchar(50)
SELECT @s = CASE
WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year] ) + '-01-01') = @date THEN 'New Year'
WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year]+1) + '-01-01') = @date THEN 'New Year'
WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year] ) + '-07-04') = @date THEN 'Independence Day'
WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year] ) + '-12-25') = @date THEN 'Christmas Day'
--WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year]) + '-12-31') = @date THEN 'New Years Eve'
--WHEN dbo.ShiftHolidayToWorkday(CONVERT(varchar, [Year]) + '-11-11') = @date THEN 'Veteran''s Day'
WHEN [Month] = 1 AND [DayOfMonth] BETWEEN 15 AND 21 AND [DayName] = 'Monday' THEN 'Martin Luther King Day'
WHEN [Month] = 5 AND [DayOfMonth] >= 25 AND [DayName] = 'Monday' THEN 'Memorial Day'
WHEN [Month] = 9 AND [DayOfMonth] <= 7 AND [DayName] = 'Monday' THEN 'Labor Day'
WHEN [Month] = 11 AND [DayOfMonth] BETWEEN 22 AND 28 AND [DayName] = 'Thursday' THEN 'Thanksgiving Day'
WHEN [Month] = 11 AND [DayOfMonth] BETWEEN 23 AND 29 AND [DayName] = 'Friday' THEN 'Day After Thanksgiving'
ELSE NULL END
FROM (
SELECT
[Year] = YEAR(@date),
[Month] = MONTH(@date),
[DayOfMonth] = DAY(@date),
[DayName] = DATENAME(weekday,@date)
) c
RETURN @s
END
GO
create FUNCTION [dbo].GetHolidays(@year int)
RETURNS TABLE
AS
RETURN (
select dt, dbo.GetHoliday(dt) as Holiday
from (
select dateadd(day, number, convert(varchar,@year) + '-01-01') dt
from master..spt_values
where type='p'
) d
where year(dt) = @year and dbo.GetHoliday(dt) is not null
)
create proc UpdateHolidaysTable
as
if not exists(select TABLE_NAME from INFORMATION_SCHEMA.TABLES where TABLE_NAME = 'Holidays')
create table Holidays(dt date primary key clustered, Holiday varchar(50))
declare @year int
set @year = 1990
while @year < year(GetDate()) + 20
begin
insert into Holidays(dt, Holiday)
select a.dt, a.Holiday
from dbo.GetHolidays(@year) a
left join Holidays b on b.dt = a.dt
where b.dt is null
set @year = @year + 1
end
create FUNCTION [dbo].[GetWorkDays](@StartDate DATE = NULL, @EndDate DATE = NULL)
RETURNS INT
AS
BEGIN
IF @StartDate IS NULL OR @EndDate IS NULL
RETURN 0
IF @StartDate >= @EndDate
RETURN 0
DECLARE @Days int
SET @Days = 0
IF year(@StartDate) * 100 + datepart(week, @StartDate) = year(@EndDate) * 100 + datepart(week, @EndDate)
--same week
select @Days = (DATEDIFF(dd, @StartDate, @EndDate))
- (CASE WHEN DATENAME(dw, @StartDate) = 'Sunday' THEN 1 ELSE 0 END)
- (CASE WHEN DATENAME(dw, @EndDate) = 'Saturday' THEN 1 ELSE 0 END)
- (select count(*) from Holidays where dt between @StartDate and @EndDate)
ELSE
--diff weeks
select @Days = (DATEDIFF(dd, @StartDate, @EndDate) + 1)
- (DATEDIFF(wk, @StartDate, @EndDate) * 2)
- (CASE WHEN DATENAME(dw, @StartDate) = 'Sunday' THEN 1 ELSE 0 END)
- (CASE WHEN DATENAME(dw, @EndDate) = 'Saturday' THEN 1 ELSE 0 END)
- (select count(*) from Holidays where dt between @StartDate and @EndDate)
RETURN @Days
END