PHP - 从开始日期开始获取天数

Case One:

$start_date = 01-Mar-15
$end_date = 31-Apr-15

Fetch number of days for start-end date. Here it will be 31 days for both the dates.

Case One:

$start_date = 16-Mar-15
$end_date = 15-Apr-15

Here it will not be the same so fetch number of days for start_date i.e. 30 days.

How can I execute below condition based on above use-cases:

if($start_date_month_days == $end_date_month_days){
//do something with 31 dates
}else{
//do something with number of days for $start_date month
}

P.S. : I am not looking for number of days between two dates. But to fetch the number of days for specific start-end dates. That dates cold be in same/different months

  $start_date = "01-Mar-15";
    $end_date = "31-Apr-15";

    $date1 = new DateTime(date("Y-m-d",strtotime($start_date)));
    $date2 = new DateTime(date("Y-m-d",strtotime($end_date)));
    $interval = $date1->diff($date2);

    echo "".$interval->d." days";

if($interval->d=="31"){
//do something
}
else{
}

Try this code