Re: Re: date calculation

If you're using a database, it may be able to take care of this for you. If you're using mysql: 6.3.4 Date and Time Functions http://www.mysql.com/documentation/mysql/bychapter/manual_Reference.html#Date_and_time_functions olinux --- Fred Merritt <fred@argus.pt> wrote: > Qt, > The easiest way is to convert your dates into a > serial day number(i.e. > the number of days that have elapsed between your > date, and some > arbitrary date in the dim and distant past - I think > PHP uses 25th > November, -4714). There are some calendar functions > in php that will do > this for you. Once you have your dates as a numeric > offset, you can > subtract them to get a the number of days between > the dates, or you can > add or subtract a number of days to get a new > offset. Once you have the > new offset, there are reverse calendar functions in > php, to convert your > new offset back to a calendar date. > > Check out the functions GregorianToJD(), and > JDToGregorian(), in the > Calendar functions of the PHP manual. If you do not > have access to the > calendar functions in your version of php, there are > also a couple of > examples how to do one of the conversions written in > PHP, in the user > contributed notes of the manual. There are also > many published articles > describing algorithms on how to do this. I can > remember implementing > these functions in 1977(Not in PHP of course), from > an article published > in the journal of the ACM, in 1963. > > Hope this helps. . . Fred > > Qt wrote: > > Dear Sirs, > > > > How can I add or subtract two date easily. Is > therea any lib or function > > about this. I can not find any easy way in the > manual > > > > Best Regards > > __________________________________________________ Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day http://shopping.yahoo.com