Convert SQL Server DateTime object to BIGINT (.Net ticks)

Question

I need to convert a DateTime type value to BIGINT type in .Net ticks format (number of 100-nanosecond intervals that have elapsed since 12:00:00 midnight, January 1, 0001).<

Answer 1

Tsk,

Here's the #1 recommendation simplified although I can't believe that was the top result. Surely this is built in, but at this point whatever I'm on a deadline. Refactoring took less than 1 min but maybe it'll help others who are looking for 1 stop solution.

CREATE FUNCTION [dbo].[Ticks] (@dt DATETIME)
RETURNS BIGINT
WITH SCHEMABINDING
AS
BEGIN 
DECLARE @year INT = DATEPART(yyyy, @dt)
DECLARE @month INT = DATEPART(mm, @dt)
DECLARE @day INT = DATEPART(dd, @dt)
DECLARE @hour INT = DATEPART(hh, @dt)
DECLARE @min INT = DATEPART(mi, @dt)
DECLARE @sec INT = DATEPART(ss, @dt)

DECLARE @days INT =
    CASE @month - 1
        WHEN 0 THEN 0
        WHEN 1 THEN 31
        WHEN 2 THEN 59
        WHEN 3 THEN 90
        WHEN 4 THEN 120
        WHEN 5 THEN 151
        WHEN 6 THEN 181
        WHEN 7 THEN 212
        WHEN 8 THEN 243
        WHEN 9 THEN 273
        WHEN 10 THEN 304
        WHEN 11 THEN 334
        WHEN 12 THEN 365
    END
    IF  @year % 4 = 0 AND (@year % 100  != 0 OR (@year % 100 = 0 AND @year % 400 = 0)) AND @month > 2 BEGIN
        SET @days = @days + 1
    END
RETURN CONVERT(bigint, 
    ((((((((@year - 1) * 365) + ((@year - 1) / 4)) - ((@year - 1) / 100)) + ((@year - 1) / 400)) + @days) + @day) - 1) * 864000000000) +
    ((((@hour * 3600) + CONVERT(bigint, @min) * 60) + CONVERT(bigint, @sec)) * 10000000) + (CONVERT(bigint, DATEPART(ms, @dt)) * CONVERT(bigint,10000));

END
GO