PHP5
+的DateTime对象很有用，因为它知道leap时间和夏令时，但是它需要一些扩展才能真正解决问题。我写了下面的文章来解决类似的问题。find_WeekdaysFromThisTo（）方法是蛮力的，但是，如果您的时间跨度小于2年，则可以相当快速地工作。

$tryme = new Extended_DateTime('2007-8-26');
$newer = new Extended_DateTime('2008-9-1');

print 'Weekdays From '.$tryme->format('Y-m-d').' To '.$newer->format('Y-m-d').': '.$tryme -> find_WeekdaysFromThisTo($newer) ."\n";
/*  Output:  Weekdays From 2007-08-26 To 2008-09-01: 265  */
print 'All Days From '.$tryme->format('Y-m-d').' To '.$newer->format('Y-m-d').': '.$tryme -> find_AllDaysFromThisTo($newer) ."\n";
/*  Output:  All Days From 2007-08-26 To 2008-09-01: 371   */
$timefrom = $tryme->find_TimeFromThisTo($newer);
print 'Between '.$tryme->format('Y-m-d').' and '.$newer->format('Y-m-d').' there are '.
      $timefrom['years'].' years, '.$timefrom['months'].' months, and '.$timefrom['days'].
      ' days.'."\n";
/*  Output: Between 2007-08-26 and 2008-09-01 there are 1 years, 0 months, and 5 days. */

class Extended_DateTime extends DateTime {

    public function find_TimeFromThisTo($newer) {
        $timefrom = array('years'=>0,'months'=>0,'days'=>0);

        // Clone because we're using modify(), which will destroy the object that was passed in by reference
        $testnewer = clone $newer;

        $timefrom['years'] = $this->find_YearsFromThisTo($testnewer);
        $mod = '-'.$timefrom['years'].' years';
        $testnewer -> modify($mod);

        $timefrom['months'] = $this->find_MonthsFromThisTo($testnewer);
        $mod = '-'.$timefrom['months'].' months';
        $testnewer -> modify($mod);

        $timefrom['days'] = $this->find_AllDaysFromThisTo($testnewer);
        return $timefrom;
    } // end function find_TimeFromThisTo


    public function find_YearsFromThisTo($newer) {
        /*
        If the passed is:
        not an object, not of class DateTime or one of its children,
        or not larger (after) $this
        return false
        */
        if (!is_object($newer) || !($newer instanceof DateTime) || $newer->format('U') < $this->format('U'))
            return FALSE;
        $count = 0;

        // Clone because we're using modify(), which will destroy the object that was passed in by reference
        $testnewer = clone $newer;

        $testnewer -> modify ('-1 year');
        while ( $this->format('U') < $testnewer->format('U')) {
            $count ++;
            $testnewer -> modify ('-1 year');
        }
        return $count;
    } // end function find_YearsFromThisTo


    public function find_MonthsFromThisTo($newer) {
        /*
        If the passed is:
        not an object, not of class DateTime or one of its children,
        or not larger (after) $this
        return false
        */
        if (!is_object($newer) || !($newer instanceof DateTime) || $newer->format('U') < $this->format('U'))
            return FALSE;

        $count = 0;
        // Clone because we're using modify(), which will destroy the object that was passed in by reference
        $testnewer = clone $newer;
        $testnewer -> modify ('-1 month');

        while ( $this->format('U') < $testnewer->format('U')) {
            $count ++;
            $testnewer -> modify ('-1 month');
        }
        return $count;
    } // end function find_MonthsFromThisTo


    public function find_AllDaysFromThisTo($newer) {
        /*
        If the passed is:
        not an object, not of class DateTime or one of its children,
        or not larger (after) $this
        return false
        */
        if (!is_object($newer) || !($newer instanceof DateTime) || $newer->format('U') < $this->format('U'))
            return FALSE;

        $count = 0;
        // Clone because we're using modify(), which will destroy the object that was passed in by reference
        $testnewer = clone $newer;
        $testnewer -> modify ('-1 day');

        while ( $this->format('U') < $testnewer->format('U')) {
            $count ++;
            $testnewer -> modify ('-1 day');
        }
        return $count;
    } // end function find_AllDaysFromThisTo


    public function find_WeekdaysFromThisTo($newer) {
        /*
        If the passed is:
        not an object, not of class DateTime or one of its children,
        or not larger (after) $this
        return false
        */
        if (!is_object($newer) || !($newer instanceof DateTime) || $newer->format('U') < $this->format('U'))
            return FALSE;

        $count = 0;

        // Clone because we're using modify(), which will destroy the object that was passed in by reference
        $testnewer = clone $newer;
        $testnewer -> modify ('-1 day');

        while ( $this->format('U') < $testnewer->format('U')) {
            // If the calculated day is not Sunday or Saturday, count this day
            if ($testnewer->format('w') != '0' && $testnewer->format('w') != '6')
                $count ++;
            $testnewer -> modify ('-1 day');
        }
        return $count;
    } // end function find_WeekdaysFromThisTo

    public function set_Day($newday) {
        if (is_int($newday) && $newday > 0 && $newday < 32 && checkdate($this->format('m'),$newday,$this->format('Y')))
            $this->setDate($this->format('Y'),$this->format('m'),$newday);
    } // end function set_Day


    public function set_Month($newmonth) {
        if (is_int($newmonth) && $newmonth > 0 && $newmonth < 13)
            $this->setDate($this->format('Y'),$newmonth,$this->format('d'));
    } // end function set_Month


    public function set_Year($newyear) {
        if (is_int($newyear) && $newyear > 0)
            $this->setDate($newyear,$this->format('m'),$this->format('d'));
    } // end function set_Year
} // end class Extended_DateTime