Datediff，不包括周末

DATEDIFF(date1, date2)

CREATE FUNCTION dbo.WorkingDaysBetween (@StartDate DATE, @EndDate DATE)
RETURNS INT
AS
BEGIN
    DECLARE @TotalDays INT = DATEDIFF(DAY, @StartDate, @EndDate)
    DECLARE @WeekendDays INT = 0
    DECLARE @CurrentDate DATE = @StartDate

    WHILE @CurrentDate <= @EndDate
    BEGIN
        IF DATEPART(WEEKDAY, @CurrentDate) IN (1, 7) -- 1=Sunday, 7=Saturday
            SET @WeekendDays = @WeekendDays + 1
        SET @CurrentDate = DATEADD(DAY, 1, @CurrentDate)
    END

    RETURN @TotalDays - @WeekendDays
END

SELECT dbo.WorkingDaysBetween('2023-10-01', '2023-10-31') AS WorkingDays;