Calculate gregorian easter sunday using a table valued function

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Calculate gregorian easter sunday using a table valued function

robin.langell

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August 22, 2014 at 10:42 am

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ChrisM@Work SSC Guru Points: 186127 More actions · Answer 1

Faster than the usual algorithm I use. Here's a little tidyup:

;WITH

Step1 AS( SELECT a = @year%19, b = FLOOR(1.0*@year/100), c = @year%100),

Step2 AS( SELECT a,b,c,d = FLOOR(1.0*b/4), e=b%4, f=FLOOR((8.0+b)/25) FROM Step1),

Step3 AS( SELECT a,b,c,d,e,g = FLOOR((1.0+ b- f)/3) FROM Step2),

Step4 AS( SELECT a,d,e,h = (19*a+b-d-g+15)%30, i= FLOOR(1.0*c/4), k= @year%4 FROM Step3),

Step5 AS( SELECT a,h,l = (32.0+2*e+2*i-h-k)%7 FROM Step4),

Step6 AS( SELECT h,l,m = FLOOR((1.0*a+11*h+22*l)/451) FROM Step5)

SELECT easterSunday = DATEFROMPARTS(@Year, FLOOR((1.0*h+l-7*m+114)/31), 1+(h+l-7*m+114)%31)

FROM Step6

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

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