Date subtraction in days

[mralston]

How do I find the difference between two dates in days?

E.g. 08/01/2004 - 05/01/2004 = 3 days

The actual dates to be used will be in MySQL datetime format (yyyy-mm-dd), but I don't think that really matters for this question.

I'm sure this should be really simple, but I just can't figure it out!

[kows]

I'm guessing you should convert both to the UNIX timestamp, and then take the less recent away from the more recent.. although I have no idea what functions you would use, I'm sure there are some that would work fine.. First, you could try jdtounix() (Julian Day to Unix), or you could just try using the MySQL function "UNIX_TIMESTAMP", like:

SELECT UNIX_TIMESTAMP(field) FROM table

hmm, I'm not actually sure of what any of these will actually return, but maybe it can help you out or get you started.. I'll look around when I get home.

edit: After looking at the PHP.net time() function, I looked up "mktime()", which converts a MySQL time to a UNIX time stamp..

check out mktime(), http://ca2.php.net/manual/en/function.mktime.php. If it doesn't work for you, check out gmmktime() too.

[kows]

ok, hmm, I found what you needed.. it was on PHP.net under checkdate()

//moon at justmoon dot de
//07-Dec-2003 01:18 

function diff_days($start_date, $end_date){
   return floor(abs(strtotime($start_date) - strtotime($end_date))/86400);
}

// You can use whatever days you want
echo diff_days("20031013", "20040105"); // result: 84

// You can use every format strtotime supports
echo diff_days("now", "-1 year");

// You can mix start and end
echo diff_days("20031203", "20031201"); // result: 2 

Hope that helps you out.

http://ca2.php.net/manual/en/function.checkdate.php

[mralston]

Thanks very much.