两个日期之间的日期持续时间，不包括存储在我的数

Question

我想计算不包括存储在我的数据库中的假期的天数。 但是我收到了错误：

  

致命错误：调用未定义的函数isWithinDates（）

$holidays = array();
$get_holidays = mysqli_query($link,"SELECT * FROM holiday_list");
while ($fetch_holidays = mysqli_fetch_array($get_holidays)){
    $holidays[]=$fetch_holidays['holiday_date'];
}
echo $begin_date = $emp_leave_data['startDate'];
echo $end_date = $last_date;
$exclude = 0;

// Loop over holidays to find out whether they are in the range
foreach ($holidays as $holiday) {
    if (isWithinDates(new DateTime($holiday), $begin_date, $end_date)) {
        $exclude++;
    }
}

function isWithinDates(DateTime $date, DateTime $start, DateTime $end)
{
    return $date >= $start && $date <= $end;
}

// Get the amount of days between our start date and the end date
// and subtract the amount of days that we know to be holidays
echo $duration = $begin_date->diff($end_date)->days - $exclude + 1;