Individuare se presente l'ora legale

dbo.summertime(iv_year, iv_month, iv_day) as SummerTime

create function SummerTime(@Year int, @Month int, @Day int)

returns int
as
    begin

    declare @SummerTime int, @aa int, @bb int, @cc int, @STBeg_y int, @STBeg_m int, @STBeg_d int, @STEnd_y int, @STEnd_m int, @STEnd_d int

    set @aa = -CEILING(-5*@Year/4)
    set @bb = @aa+4
    set @cc = @aa+1

    set @STBeg_y = @Year
    set @STBeg_m = 3
    set @STBeg_d = 31-(@bb+7*CEILING(-@bb/7)) 

    set @STEnd_y = @Year
    set @STEnd_m = 10
    set @STEnd_d = 31-(@cc+7*CEILING(-@cc/7))

    set @SummerTime = CASE WHEN
        dbo.date(@Year, @Month, @Day) >= dbo.date(@STBeg_y, @STBeg_m, @STBeg_d) and
        dbo.date(@Year, @Month, @Day) <  dbo.date(@STEnd_y, @STEnd_m, @STEnd_d) then 1 else 0 end

    return @SummerTime    
    end
go

create function Date(@Year int, @Month int, @Day int)

returns datetime
as
    begin
    return dateadd(month,(12*@Year)-22801+@Month,@Day-1)
    end
go