The number of days between dates

[mrgrammar]

I need to know how many days there are between two particular dates. For example, there are 7 days from 2004-02-06 to 2004-02-12.

I have already figured out a way of figuring the difference.

$astartdate = $_POST[startdate]; 
$aenddate = $_POST[enddate]; 
$stmonth = substr($astartdate,5,2);
$stday = substr($astartdate,8,2);
$endmonth = substr($aenddate,5,2);
$endday = substr($aenddate,8,2);

if ($stmonth == $endmonth){
	$rowct = ($endday - $stday) + 1;
}

Of course, this does not account for start and end dates that are in two different months. That's where everything gets long and convoluted.

The $startdate and $enddate fields have a field type of: date

Please provide suggestions and examples. Thanks in advance for your help.

Brian
a.k.a. MrGrammar

[LordShryku]

If this is from a mysql database, why just use datediff?
http://www.mysql.com/doc/en/Date_and_time_functions.html

[Shrike]

The datediff functions are in a fairly new version of MySQL I think. Calculating date diff is quite hard manually, PEAR has a class which can do it, also there are some useful user submitted functions on www.php.net.

[LordShryku]

And I'm fairly sure we just answered a question just like this that should be able to lead in the right direction. Of course, you'd have to search the forums a little bit.

BTW, datediff works in the latest stable release of MySQL

[mrgrammar]

To follow up, I went ahead and manually figured it out. It will also handle leap years for the next 11 years. I welcome feedback to the code.

<?PHP //**** GET VARIABLES **********
$amoviename = $POST[moviename];
$astartdate = $POST[startdate];
$aenddate = $_POST[enddate];
$stmonth = substr($astartdate,5,2);
$stday = substr($astartdate,8,2);
$styear = substr($astartdate,0,4);
$endmonth = substr($aenddate,5,2);
$endday = substr($aenddate,8,2);
$endyear = substr($enddate,0,2);

// --- GET THE LAST DAY OF THE MONTH
if ($stmonth == 01){$alength = 31;}
		if ($styear == 2004){$alength = 29;}elseif ($styear == 2008){$alength = 29;}else{$alength = 28;}}
	elseif ($stmonth == 03){$alength = 31;}
	elseif ($stmonth == 04){$alength = 30;}
	elseif ($stmonth == 05){$alength = 31;}
	elseif ($stmonth == 06){$alength = 30;}
	elseif ($stmonth == 07){$alength = 31;}
	elseif ($stmonth == 08){$alength = 31;}
	elseif ($stmonth == 09){$alength = 30;}
	elseif ($stmonth == 10){$alength = 31;}
	elseif ($stmonth == 11){$alength = 30;}
	elseif ($stmonth == 12){$alength = 31;}

?>

	    <h2>Enter Showtimes</h2>
		<p><b><font size=3>Movie: <? echo $amoviename ?></font></b> (ID: <? echo $movieid ?>)</p>
		<p>Days showing: <? echo $rowct ?></p>

		<form name="form1" method="post" action="">
			<table width="98%" border="1" cellspacing="3" cellpadding="2">

		<?PHP
			// --- IF THE START AND END DATES ARE IN THE SAME MONTH, IT'S EASY
			if ($stmonth == $endmonth){
				$rowct = ($endday - $stday) + 1;
				$limit = $rowct;

				$inputday = $stday;

				for ($i=0; $i<$limit; $i++){ 
					// --- BUILD THE INPUT DATE
					$inputdate = $styear."-".$stmonth."-".$inputday;

					// --- SHOW THE CHART
					echo "	<tr><td>".$inputdate."</td>
								<td>TimeA[".$inputday."]</td>
								<td>TimeB[".$inputday."]</td>
								<td>TimeC[".$inputday."]</td>
								<td>TimeD[".$inputday."]</td>
								<td>TimeE[".$inputday."]</td>
								<td>TimeF[".$inputday."]</td>
							</tr>";
					$inputday = $inputday + 1;
					if ($inputday < 10){$inputday = "0".$inputday;}
				}
			}

			// --- IF THE START AND END DATES ARE NOT IN THE SAME MONTH, IT'S DOABLE
			elseif ($stmonth != $endmonth){
				$prevdays = $alength - $stday;  // tells me the days in the first month
				$rowct = $endday + $prevdays + 1;
				$limit = $rowct;

				$inputday = $stday;

				for ($i=0; $i<$limit; $i++){ 
					// --- BUILD THE INPUT DATE
					if ($inputday == $alength + 1){$inputday = "01";}
					$inputdate = $styear."-".$stmonth."-".$inputday;

					// --- SHOW THE CHART
					echo "	<tr><td>".$inputdate."</td>
								<td>TimeA[".$inputday."]</td>
								<td>TimeB[".$inputday."]</td>
								<td>TimeC[".$inputday."]</td>
								<td>TimeD[".$inputday."]</td>
								<td>TimeE[".$inputday."]</td>
								<td>TimeF[".$inputday."]</td>
							</tr>";
					$inputday = $inputday + 1;
					if ($inputday < 10){$inputday = "0".$inputday;}
				}
			}

		?>

			</table>
		</form>