php函数-计算两个日期相差多少天

<?PHP

/*
*
*函数功能：计算两个以YYYY-MM-DD为格式的日期，相差几天
*
*/
function getChaBetweenTwoDate($date1,$date2){

$Date_List_a1=explode("-",$date1);
$Date_List_a2=explode("-",$date2);

$d1=mktime(0,0,0,$Date_List_a1[1],$Date_List_a1[2],$Date_List_a1[0]);

$d2=mktime(0,0,0,$Date_List_a2[1],$Date_List_a2[2],$Date_List_a2[0]);

$Days=round(($d1-$d2)/3600/24);

return $Days;
}

echo getChaBetweenTwoDate('2010-08-11','2010-08-16');
echo "<br>";
echo getChaBetweenTwoDate('2010-08-16','2010-08-11');
?>

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