Subtracting dates and converting them to days

[Max_CR]

Hi everyone,

I am trying to design a code to ask someone for the start date and end date of their construction project. I would then like to count the amount of days between the start date and end date of their project. Then, I would like to create a progress bar to show people the progress of their new project so that when they log into their account they can see its progress.

I have a few ideas about how to move forward with this - but those ideas are complicated and inefficient.

Could anyone tell me how I might be able to do this or start me on this?

Thanks!

[bradgrafelman]

Are these dates coming from a MySQL DB, by any chance? If so, just use MySQL's DATEDIFF().

[Max_CR]

Thanks Brad but it is not coming from an SQL database.

[bradgrafelman]

Any reason why not? I guess I don't understand what you're doing... where do the dates come from? Are you just going to have a form where you input a couple of dates and immediately display the result without storing anything for subsequent visits?

Either way, if I had to do it strictly in PHP, I'd probably use the DateTime::diff() method (man page: [man]DateTime.diff[/man]) to get the difference between two [man]DateTime[/man] objects.

[Max_CR]

Thanks. I created the code below.

	$start_date = $_REQUEST['start_year']."-".$_REQUEST['start_month']."-".$_REQUEST['start_day'];
	$end_date = $_REQUEST['end_year']."-".$_REQUEST['end_month']."-".$_REQUEST['end_day'];

$start_date=date_create($start_date);
$end_date=date_create($end_date);


$difference = date_diff($start_date, $end_date);
echo $difference->format('%R%a days');

and I get the following error message

Fatal error: Call to undefined function date_diff() in /home1/alphaa/public_html/uploader_new.php on line 9

[bradgrafelman]

Sounds like you aren't using the latest version of PHP5 (e.g. version 5.3.x). Guess I forgot to mention I would also use the latest stable release of PHP. :p

For PHP < 5.3.0, you could always use the function suggested in this user-contributed note on the manual page for [man]date_diff/man.

[Max_CR]

Thanks! Here is the code I have. It still doesn't work correctly. THe dates are in the format: "20 January 2011" for example.

    $startDate = $_REQUEST['start_day']." ".$_REQUEST['start_month']." ".$_REQUEST['start_year']; 
    $endDate = $_REQUEST['end_day']." ".$_REQUEST['end_month']." ".$_REQUEST['end_year']; 

///begin provided code for date difference
        function dateDifference($startDate, $endDate) 
        { 
            $startDate = strtotime($startDate); 
            $endDate = strtotime($endDate); 
            if ($startDate === false || $startDate < 0 || $endDate === false || $endDate < 0 || $startDate > $endDate) 
                return false; 

        $years = date('Y', $endDate) - date('Y', $startDate); 

        $endMonth = date('m', $endDate); 
        $startMonth = date('m', $startDate); 

        // Calculate months 
        $months = $endMonth - $startMonth; 
        if ($months <= 0)  { 
            $months += 12; 
            $years--; 
        } 
        if ($years < 0) 
            return false; 

        // Calculate the days 
                    $offsets = array(); 
                    if ($years > 0) 
                        $offsets[] = $years . (($years == 1) ? ' year' : ' years'); 
                    if ($months > 0) 
                        $offsets[] = $months . (($months == 1) ? ' month' : ' months'); 
                    $offsets = count($offsets) > 0 ? '+' . implode(' ', $offsets) : 'now'; 

                    $days = $endDate - strtotime($offsets, $startDate); 
                    $days = date('z', $days);    

        return array($years, $months, $days); 
    } 
///end provided code for date difference


   $difference = dateDifference($startDate, $endDate); 
echo$difference;