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

I have found a CodeProject article that may assist: Convert DateTime To .NET Ticks Using T-SQL

I enclose the SQL function from the above article (I hope this is ok? As it requires registration.)

CREATE FUNCTION [dbo].[MonthToDays365] (@month int)
RETURNS int
WITH SCHEMABINDING
AS
-- converts the given month (0-12) to the corresponding number of days into the year (by end of month)
-- this function is for non-leap years
BEGIN 
RETURN
    CASE @month
        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
        ELSE 0
    END
END

GO

CREATE FUNCTION [dbo].[MonthToDays366] (@month int)
RETURNS int 
WITH SCHEMABINDING
AS
-- converts the given month (0-12) to the corresponding number of days into the year (by end of month)
-- this function is for leap years
BEGIN 
RETURN
    CASE @month
        WHEN 0 THEN 0
        WHEN 1 THEN 31
        WHEN 2 THEN 60
        WHEN 3 THEN 91
        WHEN 4 THEN 121
        WHEN 5 THEN 152
        WHEN 6 THEN 182
        WHEN 7 THEN 213
        WHEN 8 THEN 244
        WHEN 9 THEN 274
        WHEN 10 THEN 305
        WHEN 11 THEN 335
        WHEN 12 THEN 366
        ELSE 0
    END
END

GO

CREATE FUNCTION [dbo].[MonthToDays] (@year int, @month int)
RETURNS int
WITH SCHEMABINDING
AS
-- converts the given month (0-12) to the corresponding number of days into the year (by end of month)
-- this function is for non-leap years
BEGIN 
RETURN 
    -- determine whether the given year is a leap year
    CASE 
        WHEN (@year % 4 = 0) and ((@year % 100  != 0) or ((@year % 100 = 0) and (@year % 400 = 0))) THEN dbo.MonthToDays366(@month)
        ELSE dbo.MonthToDays365(@month)
    END
END

GO

CREATE FUNCTION [dbo].[TimeToTicks] (@hour int, @minute int, @second int)  
RETURNS bigint 
WITH SCHEMABINDING
AS 
-- converts the given hour/minute/second to the corresponding ticks
BEGIN 
RETURN (((@hour * 3600) + CONVERT(bigint, @minute) * 60) + CONVERT(bigint, @second)) * 10000000
END

GO

CREATE FUNCTION [dbo].[DateToTicks] (@year int, @month int, @day int)
RETURNS bigint
WITH SCHEMABINDING
AS
-- converts the given year/month/day to the corresponding ticks
BEGIN 
RETURN CONVERT(bigint, (((((((@year - 1) * 365) + ((@year - 1) / 4)) - ((@year - 1) / 100)) + ((@year - 1) / 400)) + dbo.MonthToDays(@year, @month - 1)) + @day) - 1) * 864000000000;
END

GO

CREATE FUNCTION [dbo].[DateTimeToTicks] (@d datetime)
RETURNS bigint
WITH SCHEMABINDING
AS
-- converts the given datetime to .NET-compatible ticks
-- see https://msdn.microsoft.com/en-us/library/system.datetime.ticks(v=vs.110).aspx
BEGIN 
RETURN 
    dbo.DateToTicks(DATEPART(yyyy, @d), DATEPART(mm, @d), DATEPART(dd, @d)) +
    dbo.TimeToTicks(DATEPART(hh, @d), DATEPART(mi, @d), DATEPART(ss, @d)) +
    (CONVERT(bigint, DATEPART(ms, @d)) * CONVERT(bigint,10000));
END

GO