Question

In my older post, I tried to change the date to current date and add 8 hours time.

SQL Server: convert to today then add 8 hours

UPDATE business.dbo.db_schedule
SET nextUpdate= DATEADD(hh, 8,
                DATEADD(d, DATEDIFF(D,nextUpdate,Getdate()),
                          nextUpdate))
where sno=8

note: nextUpdate may be any time in the past.

if I want to go one step further; I want nextdate to be in the future time.
Because if I add 8 hour once, the result may be still a time in the past, I may have to add one more (or even twice) so the result is in the future. Can i do it in one step?

Answer 1

UPDATE business.dbo.db_schedule
SET nextUpdate =
  DATEADD(HOUR
    , 8 * CEILING((DATEDIFF(MILLISECOND, nextUpdate, GETDATE()) / 3600000.) / 8.)
    , nextUpdate)
  )
WHERE sno = 8;

Instead of just adding 8 hours, we multiply 8 by the CELING of the number of hours apart nextUpdate is from GETDATE()

e.g. If nextUpdate is 2012-10-01 02:30:00 and GETDATE() is currently 2012-10-02 15:15:00, then there are 36.75 (rounded up to 37) Hours difference. The CEILING of 37 / 8 is 5, which means you will need to add 5 * 8 hours to get a time that is after GETDATE() yet retains the multiple of 8 hours from your current nextUpdate value.

SQLFiddle example of the solution