Easter Eggs?

Create Date Table With UK & Easter Bank Holidays

Also includes ISOWeek & Weekends

Dont know whether this is of any use to anyone or it has been done before but there are a lot of posts on here regarding date calculation issues & usually the most straight forward answer is to compare against a table of dates.

So while looking at Bretts blog and another post on here, i thought i'd post this on here
http://weblogs.sqlteam.com/brettk/archive/2005/05/12/5139.aspx
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=49698

Special thanks to rockmoose & BOL (as always)

Edit: It also moves bank holidays to the following Monday (and Tuesday - xmas) if the bank holiday(s) falls on the weekend

SET DATEFIRST 1
SET NOCOUNT ON
GO

--Create ISO week Function (thanks BOL)
CREATE FUNCTION ISOweek (@DATE datetime)
RETURNS int
AS
BEGIN
DECLARE @ISOweek int
SET @ISOweek= DATEPART(wk,@DATE)+1
-DATEPART(wk,CAST(DATEPART(yy,@DATE) as CHAR(4))+'0104')
--Special cases: Jan 1-3 may belong to the previous year
IF (@ISOweek=0)
SET @ISOweek=dbo.ISOweek(CAST(DATEPART(yy,@DATE)-1
AS CHAR(4))+'12'+ CAST(24+DATEPART(DAY,@DATE) AS CHAR(2)))+1
--Special case: Dec 29-31 may belong to the next year
IF ((DATEPART(mm,@DATE)=12) AND
((DATEPART(dd,@DATE)-DATEPART(dw,@DATE))>= 28))
SET @ISOweek=1
RETURN(@ISOweek)
END
GO
--END ISOweek

--CREATE Easter algorithm function
--Thanks to Rockmoose (http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=45689)
CREATE FUNCTION fnDLA_GetEasterdate(@year INT)
RETURNS CHAR (8)
AS
BEGIN
-- Easter date algorithm of Delambre
DECLARE @A INT,@B INT,@C INT,@D INT,@E INT,@F INT,@G INT,
@H INT,@I INT,@K INT,@L INT,@M INT,@O INT,@R INT

SET @A = @YEAR%19
SET @B = @YEAR / 100
SET @C = @YEAR%100
SET @D = @B / 4
SET @E = @B%4
SET @F = (@B + 8) / 25
SET @G = (@B - @F + 1) / 3
SET @H = ( 19 * @A + @B - @D - @G + 15)%30
SET @I = @C / 4
SET @K = @C%4
SET @L = (32 + 2 * @E + 2 * @I - @H - @K)%7
SET @M = (@A + 11 * @H + 22 * @L) / 451
SET @O = 22 + @H + @L - 7 * @M

IF @O > 31
BEGIN
SET @R = @O - 31 + 400 + @YEAR * 10000
END
ELSE
BEGIN
SET @R = @O + 300 + @YEAR * 10000
END

RETURN @R
END
GO
--END fnDLA_GetEasterdate

--Create the table
CREATE TABLE MyDateTable
(
FullDate datetime NOT NULL CONSTRAINT PK_FullDate PRIMARY KEY CLUSTERED,
Period int,
ISOWeek int,
WorkingDay varchar(1) CONSTRAINT DF_MyDateTable_WorkDay DEFAULT 'Y'
)
GO
--End table create

--Populate table with required dates
DECLARE @DateFrom datetime, @DateTo datetime, @Period int
SET @DateFrom = CONVERT(datetime,'20000101') --yyyymmdd (1st Jan 2000) amend as required
SET @DateTo = CONVERT(datetime,'20991231') --yyyymmdd (31st Dec 2099) amend as required
WHILE @DateFrom <= @DateTo
BEGIN
SET @Period = CONVERT(int,LEFT(CONVERT(varchar(10),@DateFrom,112),6))
INSERT MyDateTable(FullDate, Period, ISOWeek)
SELECT @DateFrom, @Period, dbo.ISOweek(@DateFrom)
SET @DateFrom = DATEADD(dd,+1,@DateFrom)
END
GO
--End population


/* Start of WorkingDays UPDATE */
UPDATE MyDateTable
SET WorkingDay = 'B' --B = Bank Holiday
--------------------------------EASTER---------------------------------------------
WHERE FullDate = DATEADD(dd,-2,CONVERT(datetime,dbo.fnDLA_GetEasterdate(DATEPART(yy,FullDate)))) --Good Friday
OR FullDate = DATEADD(dd,+1,CONVERT(datetime,dbo.fnDLA_GetEasterdate(DATEPART(yy,FullDate)))) --Easter Monday
GO

UPDATE MyDateTable
SET WorkingDay = 'B'
--------------------------------NEW YEAR-------------------------------------------
WHERE FullDate IN (SELECT MIN(FullDate) FROM MyDateTable
WHERE DATEPART(mm,FullDate) = 1 AND DATEPART(dw,FullDate) NOT IN (6,7)
GROUP BY DATEPART(yy,FullDate))
---------------------MAY BANK HOLIDAYS(Always Monday)------------------------------
OR FullDate IN (SELECT MIN(FullDate) FROM MyDateTable
WHERE DATEPART(mm,FullDate) = 5 AND DATEPART(dw,FullDate) = 1
GROUP BY DATEPART(yy,FullDate))
OR FullDate IN (SELECT MAX(FullDate) FROM MyDateTable
WHERE DATEPART(mm,FullDate) = 5 AND DATEPART(dw,FullDate) = 1
GROUP BY DATEPART(yy,FullDate))
--------------------AUGUST BANK HOLIDAY(Always Monday)------------------------------
OR FullDate IN (SELECT MAX(FullDate) FROM MyDateTable
WHERE DATEPART(mm,FullDate) = 8 AND DATEPART(dw,FullDate) = 1
GROUP BY DATEPART(yy,FullDate))
--------------------XMAS(Move to next working day if on Sat/Sun)--------------------
OR FullDate IN (SELECT CASE WHEN DATEPART(dw,FullDate) IN (6,7) THEN
DATEADD(dd,+2,FullDate) ELSE FullDate END
FROM MyDateTable
WHERE DATEPART(mm,FullDate) = 12 AND DATEPART(dd,FullDate) IN (25,26))
GO

---------------------------------------WEEKENDS--------------------------------------
UPDATE MyDateTable
SET WorkingDay = 'N'
WHERE DATEPART(dw,FullDate) IN (6,7)
GO
/* End of WorkingDays UPDATE */

--SELECT * FROM MyDateTable ORDER BY 1
DROP FUNCTION fnDLA_GetEasterdate
DROP FUNCTION ISOweek
--DROP TABLE MyDateTable

SET NOCOUNT OFF


Andy

Beauty is in the eyes of the beerholder