sql工作日假期

Question

I've seen different version of this kind of function for other coding languages (Python, jQuery, etc.) but not for SQL. I have a procedure that needs to have a date calculated that is 65 days from the creation date, but it cannot include weekend or holidays. We already have a function that is able to add only working days to a date, but not take into account holidays. We have a holiday table that lists all the holiday dates, tblHolidayDates with a column HolidayDate in standard date format.

How would I do this? I'd also consider maybe just creating a Calendar table as well if someone could give me a CREATE TABLE query for that - all it would need is dates, weekday, and holiday columns.

Below I have given the current loop function that adds business days, but it's missing holidays. Any help would be greatly appreciated!!

ALTER FUNCTION [dbo].[AddWorkDaysToDate]
(   
@fromDate       datetime,
@daysToAdd      int
)
RETURNS datetime
AS
BEGIN   
DECLARE @toDate datetime
DECLARE @daysAdded integer

-- add the days, ignoring weekends (i.e. add working days)
set @daysAdded = 1
set @toDate = @fromDate

while @daysAdded <= @daysToAdd
begin
-- add a day to the to date
set @toDate = DateAdd(day, 1, @toDate)
-- only move on a day if we've hit a week day
if (DatePart(dw, @toDate) != 1) and (DatePart(dw, @toDate) != 7)
begin
    set @daysAdded = @daysAdded + 1
end
end

RETURN @toDate

END

Answer 1

I wrote a SQL function years ago to build a dynamic holiday table as a table function. The link is below:

http://www.joebooth-consulting.com/sqlServer/sqlServer.html#CalendFunc

Hope it helps...

You can access the table function (or your own holiday table) to determine number of holidays via a SQL statement like below

SELECT count(*) FROM holiday_date(2013)
WHERE holiday_date BETWEEN @fromDate AND @toDate

then add the count to the returned date using dateAdd().

If you might have holidays that fall on a weekend, add the following to the WHERE clause

   AND DatePart(dw, Holiday_date) != 1) and (DatePart(dw, holiday_date) != 7)

Answer 2

I've always achieved this with a static table of dates from roughly 5 years in the past to 10 in the future, each date being marked with 'working day' status and sometimes other flags as required. Previously using MS-SL server I would achieve this quickly with a WHILE loop, I think MySQL supports the same syntax

WHILE (condition)
BEGIN
 INSERT date
END

To create the table either use the Enterprise Manager UI or something like

CREATE TABLE DateTable
 (
   actual_date datetime NOT NULL,
   is_holiday bit NOT NULL
 )

Answer 3

Assuming we have a DateTable with columns actual_date (date) and is_holiday (bit) , containing all dates and where all workdays have is_holiday=0:

SELECT actual_date from 
(
    SELECT actual_date, ROW_NUMBER() OVER(ORDER BY actual_date) AS Row 
    FROM DateTable
    WHERE is_holiday= 0 and actual_date > '2013-12-01'
) X
WHERE row = 65

This will find 2013-12-01 plus 65 workdays, skipping holidays.