Date difference in Days,hours minutes and seconds.

Question

Hi All,
I have two date Suppose one is getdate() and other one is gatedate() +1 .I have to show the difference, currently I used a datediff in the stored proc which just shows the difference of the days :( but i need to show the difference in days:hours:minutes:seconds if possible.
its a countdown with the current date. Like the two fields are sale_start_date and sale_end_date. Hope i am clear.
Please let me know ASAP thanks in advance.Can anyone help me?all help is great help.
Say the difference of
12/6/2007 7:00:00 AM, 12/8/2007 8:00:00 AM  as 2 days 1:00:00)
Thanks
N

Answer 1

One of the problems of using DATEDIFF when dealing with either seconds or milliseconds is that this function will result in execution errors if the start and end dates span then entire domain of possible dates.  Below is an alternative that seems to work over the entire date domain.  A couple of things to note:
1. This select converts the days and seconds of each date into BIGINT datatypes to avoid the overflow error
2. This select uses a CROSS APPLY operator; in this case I chose CROSS APPLY to suggest the possibility of converting this select into an inline table function.
I suspect that if you dig around this forum and the net that you will find a better routine, but here is yet another alternative:
declare @test table
( startDate datetime, endDate datetime)
insert into @test values
('6/1/9', getdate()),
('6/9/9 15:15', '6/10/9 19:25:27.122'),
('6/9/9 15:15', '6/10/9 13:25:27.122'),
('6/9/9', '6/10/9 00:00:01'),
('1/1/1760', '12/31/2999')
select
  startDate,
  endDate,
  [Days],
  [Hours],
  [Minutes],
  [Seconds]
from @test
cross apply
( select
    cast((endSecond - startSecond) / 86400 as integer) as [Days],
    cast(((endSecond - startSecond) % 86400) / 3600 as tinyint) as [Hours],
    cast(((endSecond - startSecond) % 3600) / 60 as tinyint) as [Minutes],
    cast((endSecond - startSecond) % 60 as tinyint) as [Seconds]
  from
  ( select
      86400 * cast(convert(integer, convert(binary(4),
                    left(convert(binary(8), startDate),4))) as bigint)
        + cast(convert(integer, convert(binary(4),
            right(convert(binary(8), startDate),4)))/300 as bigint)
      as startSecond,
      86400 * cast(convert(integer, convert(binary(4),
                    left(convert(binary(8), endDate),4))) as bigint)
        + cast(convert(integer, convert(binary(4),
            right(convert(binary(8), endDate),4)))/300 as bigint)
      as endSecond
  ) q
) p
/* -------- Sample Output: --------
startDate               endDate                 Days        Hours Minutes Seconds
2009-06-01 00:00:00.000 2009-06-22 08:28:36.670 21          8     28      36
2009-06-09 15:15:00.000 2009-06-10 19:25:27.123 1           4     10      27
2009-06-09 15:15:00.000 2009-06-10 13:25:27.123 0           22    10      27
2009-06-09 00:00:00.000 2009-06-10 00:00:01.000 1           0     0       1
1760-01-01 00:00:00.000 2999-12-31 00:00:00.000 452900      0     0       0
(5 row(s) affected)
 EDIT:
I based the routine more-or-less on Thilla's reply.
Kent Waldrop