MS SQL Generate All Date and Times Between 2 Dates

CREATE FUNCTION generateDateTable 
(
    -- Add the parameters for the function here
    @start_date datetime
    , @end_date datetime
    , @datepart varchar(20) = 'day'
    , @step int = 1
)
returns @dates TABLE 
(
    -- Add the column definitions for the TABLE variable here
    start_date datetime, 
    end_date datetime
)
AS
begin
    -- if we're doing calculations based on the days (not time) then strip the time out
    IF( @datepart IN ('year', 'yy', 'yyyy', 'quarter', 'qq', 'q', 'month', 'mm', 'm', 'dayofyear', 'dy', 'y', 'day', 'dd', 'd', 'week', 'wk', 'ww') )
    begin
        SET @start_date = cast(floor(cast(@start_date AS float)) AS datetime)
        SET @end_date = cast(floor(cast(@end_date AS float)) AS datetime)
    end
 
    declare @new_start datetime
 
    while @start_date <= @end_date
    begin
        -- get the new starting row
        SET @new_start = (case 
            when @datepart IN ('year', 'yy', 'yyyy') then dateadd(yy, @step, @start_date)
            when @datepart IN ('quarter', 'qq', 'q') then dateadd(qq, @step, @start_date)
            when @datepart IN ('month', 'mm', 'm') then dateadd(mm, @step, @start_date) 
            when @datepart IN ('dayofyear', 'dy', 'y') then dateadd(dy, @step, @start_date) 
            when @datepart IN ('day', 'dd', 'd') then dateadd(dd, @step, @start_date) 
            when @datepart IN ('week', 'wk', 'ww') then dateadd(ww, @step, @start_date) 
            when @datepart IN ('hour', 'hh') then dateadd(hh, @step, @start_date) 
            when @datepart IN ('minute', 'mi', 'n') then dateadd(n, @step, @start_date) 
            when @datepart IN ('second', 'ss', 's') then dateadd(s, @step, @start_date) 
            when @datepart IN ('millisecond', 'ms') then dateadd(ms, @step, @start_date) 
            else dateadd(dd, @step, @start_date)
        end)
 
        -- insert a new row
        INSERT 
            @dates 
        (
            start_date
            , end_date
        ) VALUES (
            @start_date
            -- since MSSQL is only accurate to 3.33ms, we need to subtract 3 ms to get the upper range in time
            , dateadd(ms, -3, @new_start)
        )
 
        -- update the starting row
        SET @start_date = @new_start
    end
 
    RETURN 
end
 
 
 
 
 
 
SELECT
    *
FROM
    dbo.generateDateTable('12-01-2008', '12-31-2008', 'day', 1) 
/*
    Since the UDF uses a CTE to generate the data, if you're trying to output 
    a resultset that produces more than 100 rows, you'll want to use the OPTION
    directive to set the maximum recursion number to use. This is only required
    if your output would generate more than 100 records.
*/
OPTION (maxrecursion 32767)