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

    -- =============================================
-- Author:      Baran Kaynak
-- Create date: 14.03.2011
-- Description: 09:30 ile 17:30 arasındaki iş saatlerini hafta sonlarını almayarak toplar.
-- =============================================
CREATE FUNCTION [dbo].[WorkTime] 
(
    @StartDate DATETIME,
    @FinishDate DATETIME
)
RETURNS BIGINT
AS
BEGIN
    DECLARE @Temp BIGINT
    SET @Temp=0

    DECLARE @FirstDay DATE
    SET @FirstDay = CONVERT(DATE, @StartDate, 112)

    DECLARE @LastDay DATE
    SET @LastDay = CONVERT(DATE, @FinishDate, 112)

    DECLARE @StartTime TIME
    SET @StartTime = CONVERT(TIME, @StartDate)

    DECLARE @FinishTime TIME
    SET @FinishTime = CONVERT(TIME, @FinishDate)

    DECLARE @WorkStart TIME
    SET @WorkStart = '09:30'

    DECLARE @WorkFinish TIME
    SET @WorkFinish = '17:30'

    IF (@StartTime<@WorkStart)
    BEGIN
        SET @StartTime = @WorkStart
    END
    IF (@FinishTime>@WorkFinish)
    BEGIN
        SET @FinishTime=@WorkFinish
    END

    DECLARE @CurrentDate DATE
    SET @CurrentDate = CONVERT(DATE, @StartDate, 112)
    DECLARE @LastDate DATE
    SET @LastDate = CONVERT(DATE, @FinishDate, 112)

    WHILE(@CurrentDate<=@LastDate)
    BEGIN       
        IF (DATEPART(dw, @CurrentDate)!=1 AND DATEPART(dw, @CurrentDate)!=7)
        BEGIN
            IF (@CurrentDate!=@FirstDay) AND (@CurrentDate!=@LastDay)
            BEGIN
                SET @Temp = (@Temp + (9*60))
            END
            --IF it starts at startdate and it finishes not this date find diff between work finish and start as minutes
            ELSE IF (@CurrentDate=@FirstDay) AND (@CurrentDate!=@LastDay)
            BEGIN
                SET @Temp = @Temp + DATEDIFF(MINUTE, @StartTime, @WorkFinish)
            END

            ELSE IF (@CurrentDate!=@FirstDay) AND (@CurrentDate=@LastDay)
            BEGIN
                SET @Temp = @Temp + DATEDIFF(MINUTE, @WorkStart, @FinishTime)
            END
            --IF it starts and finishes in the same date
            ELSE IF (@CurrentDate=@FirstDay) AND (@CurrentDate=@LastDay)
            BEGIN
                SET @Temp = DATEDIFF(MINUTE, @StartDate, @FinishDate)
            END
        END
        SET @CurrentDate = DATEADD(day, 1, @CurrentDate)
    END

    -- Return the result of the function
    IF @Temp<0
    BEGIN
        SET @Temp=0
    END
    RETURN @Temp

END

GO