Holiday List
This function returns a table of "holidays" for any given year. Rather than build a table of holidays and update it each year, this UDF stores holiday rules as procedural logic and computes the holidays of any year...
Holiday_list()
To use the function, you should first review the code and comment out any holidays you might not want to include, or possibly add any additional holidays. There are three "rules" for computing holidays dates.
- Fixed date holiday-Holidays which fall on the same "date" each year
- Fixed day holidays-Holidays which fall on the X day of the week of the Y week of the month
- Easter holidays-Holidays that are relative to the date of Easter Sunday
Once the function contains your set of holidays, you can use the function just as you would a normal SQL table. For example, the following SQL line
SELECT * FROM holiday_list(2011) ORDER BY Holiday_date
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-- Returns a virtual table containing all holidays for a given year
---------------------------------------------------------------------------------
CREATE FUNCTION [dbo].[Holiday_List] (@nYear INT)
RETURNS @Holidays TABLE
(Holiday_name VARCHAR(32),
Holiday_date SMALLDATETIME
)
AS
BEGIN
-- Calculate Easter Sunday
DECLARE @g INT
DECLARE @c INT
DECLARE @h INT
DECLARE @i INT
DECLARE @j INT
DECLARE @l INT
DECLARE @Month INT
DECLARE @Day INT
DECLARE @Easter SMALLDATETIME
DECLARE @WorkDT SMALLDATETIME
-- Bizarre Algorithm to determine Easter Sunday
SET @g = @nYear % 19
SET @c = @nYear / 100
SET @h = ((@c - (@c / 4) - ((8 * @c + 13) / 25) + (19 * @g) + 15) % 30)
SET @i = @h - ((@h / 28) * (1 - (@h /28) * (29 / (@h + 1)) * ((21 - @g) / 11)))
SET @j = ((@nYear + (@nYear / 4) + @i + 2 - @c + (@c / 4)) % 7)
SET @l = @i - @j
SET @Month = 3 + ((@l + 40) / 44)
SET @Day = @l + 28 - (31 * (@Month / 4))
SET @Easter = CAST(@Month AS VARCHAR(2)) + '/' + CAST(@Day As VARCHAR(2)) + '/' + CAST(@nYear AS VARCHAR(4))
------------------------------------------------------------------------------------------------
-- Add Easter Sunday to holiday list, and get holidays based around Easter
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Easter',@Easter)
-- Good Friday
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Good Friday',DateAdd(d,-2,@Easter))
-- Palm Sunday
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Palm Sunday',DateAdd(ww,-1,@Easter))
-------------------------------------------------------------------------------------------------
-- Fixed date holidays are loaded next
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('New Year''s Day',CONVERT(SmallDateTime,'1/1/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Groundhog Day',CONVERT(SmallDateTime,'2/2/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Lincoln''s Birthday',CONVERT(SmallDateTime,'2/12/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Valentines Day',CONVERT(SmallDateTime,'2/14/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('St. Patrick''s Day',CONVERT(SmallDateTime,'3/17/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('April Fools Day',CONVERT(SmallDateTime,'4/1/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Flag Day',CONVERT(SmallDateTime,'6/14/'+CAST(@nYear AS VARCHAR(4))))
IF @nYear >=1776 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Independence Day',CONVERT(SmallDateTime,'7/4/'+CAST(@nYear AS VARCHAR(4))))
IF @nYear >=1958 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Boss''s Day',CONVERT(SmallDateTime,'10/16/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Halloween',CONVERT(SmallDateTime,'10/31/'+CAST(@nYear AS VARCHAR(4))))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Christmas',CONVERT(SmallDateTime,'12/25/'+CAST(@nYear AS VARCHAR(4))))
IF @nYear >=1966 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Kwanzaa',CONVERT(SmallDateTime,'12/26/'+CAST(@nYear AS VARCHAR(4))))
-- Holidays that full on the same day of the week (based on the year they were officially established)
IF @nYear>=1983 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Martin Luther King Day',dbo.FloatingDate(3,2,1,@nYear)) -- 3rd Monday in January
IF @nYear>=1993 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Take your Daughter to Work Day',dbo.FloatingDate(4,5,4,@nYear)) -- 4th Thursday in April
IF @nYear>=1908 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Mothers Day',dbo.FloatingDate(2,1,5,@nYear)) -- 2nd Sunday in May
IF @nYear>=1950 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Armed Forces Day',dbo.FloatingDate(3,7,5,@nYear)) -- 3rd Saturday in May
IF @nYear>=1910 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Fathers Day',dbo.FloatingDate(3,1,6,@nYear)) -- 3rd Sunday in June
IF @nYear>=1894 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Labor Day',dbo.FloatingDate(1,2,9,@nYear)) -- 1st Monday in September
IF @nYear>=1941 INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Thanksgiving',dbo.FloatingDate(4,5,11,@nYear)) -- 4th Thursday in November
---------------------------------------------------------------------------------------
-- Federal holidays that only come every 4 years
---------------------------------------------------------------------------------------
IF (@nYear >= 1937) AND ((@nYear-1937) % 4)=0
BEGIN
SET @WorkDT=CONVERT(SmallDateTime,'01/20/'+CAST(@nYear AS VARCHAR(4))) -- Get Inauguration day
IF DatePart(dw,@WorkDT)=1 SET @WorkDt=DateAdd(d,1,@WorkDt) -- Move to Monday if it falls on Sunday
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Inauguration Day',@WorkDt)
END
IF (@nYear < 1937) AND ((@nYear-1937) % 4)=0
BEGIN
-- Get Inauguration day for years prior to 1937
SET @WorkDT = CONVERT(SmallDateTime,'03/04/'+CAST(@nYear AS VARCHAR(4)))
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Inauguration Day',@WorkDt)
END
---------------------------------------------------------------------------------------
-- Holidays that change based upon year
---------------------------------------------------------------------------------------
IF @nYear >= 1971
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Presidents Day',dbo.FloatingDate(3,2,2,@nYear)) -- 3rd Monday in February
IF @nYear < 1971
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Washington''s Birthday',CONVERT(SmallDateTime,'2/22/'+CAST(@nYear AS VARCHAR(4))))
IF (@nYear >=1954)
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Veteran''s Day',CONVERT(SmallDateTime,'11/11/'+CAST(@nYear AS VARCHAR(4))))
IF (@nYear >=1921 and @nYear < 1954)
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Armistice',CONVERT(SmallDateTime,'11/11/'+CAST(@nYear AS VARCHAR(4))))
IF @nYear>=1971
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Columbus Day',dbo.FloatingDate(2,2,10,@nYear)) -- 2nd Monday in October
IF @nYear>=1937 and @nYear <1971
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Columbus Day',CONVERT(SmallDateTime,'10/12/'+CAST(@nYear AS VARCHAR(4))))
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-- Day light savings start and end, based on US Federal law only
---------------------------------------------------------------------------------------
IF @nYear >= 1987 AND @nYear <2007
BEGIN
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Daylight Savings -Start',dbo.FloatingDate(1,1,4,@nYear)) -- 1st Sunday in April
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Daylight Savings -End',dbo.FloatingDate(4,1,10,@nYear)) -- 4th Sunday in October
END
IF @nYear >= 2007
BEGIN
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Daylight Savings -Start',dbo.FloatingDate(2,1,3,@nYear)) -- 2nd Sunday in March
INSERT INTO @Holidays (Holiday_name,Holiday_date) VALUES ('Daylight Savings -End',dbo.FloatingDate(1,1,11,@nYear)) -- 1st Sunday in November
END
RETURN
END
GO
CREATE FUNCTION dbo.FloatingDate(@Occur INT,@WeekDay INT,@Month INT,@Year INT)
RETURNS
SMALLDATETIME
AS
BEGIN
DECLARE @Result SMALLDATETIME
DECLARE @StartDate SMALLDATETIME
-- Get Starting date, which is first day of the month
SET @StartDate = CONVERT(SmallDateTime,CAST(@Month AS VARCHAR(2))+'/1/'+CAST(@Year AS VARCHAR(4)))
SET @Result = cast(str(@Month)+'/'+ str((7+ @Weekday-datepart(dw,@StartDate))%7+1) +'/'+str(@Year) AS datetime)+(@Occur-1)*7
RETURN @Result
END 
