alter function fnCovid (@Date datetime)

returns bigint as

begin

declare @StartDate datetime select @StartDate = '2020-04-02'

declare @DayDiff int

select @DayDiff = datediff (day, @StartDate, @Date)

declare @a decimal (20, 10), @b decimal (20, 10)

select @a = 0.00025641 * 1000000

select @b = 0.07358974 * 1000000

declare @N bigint

select @N = @a * @DayDiff * @DayDiff + @b * @DayDiff + 1000000

return @N

end

/*

creation date : 2020-04-28 00:16

modification date:

2020 04 02 - 1 MLN

2020 04 15 - 2 MLN

2020 04 27 - 3 MLN

2020 05 28 - 5 925 127

declare @Date datetime select @Date = getdate ()

select dbo.fnCovid (@Date)

select dbo.fnCovid ('2020-04-02T00:00:00.000')

select dbo.fnCovid ('2020-04-15T00:00:00.000')

select dbo.fnCovid ('2020-05-28T00:00:00.000')

select getdate ()

*/