获取月份

/*年月＋1算法 By Terry*/
function yearMonthAddOne($yearMonth){
    $year = substr($yearMonth,0,4);
    $month = substr($yearMonth,4);
    if($month!=12){
        $month = $month+1;
    }else{
        $year = $year+1;
        $month = 1;
    }
    $month = $month<10?('0'.$month):$month;
    return $year.$month;
}

if(!function_exists('get_year_months_by_time_period')){

   function get_year_months_by_time_period($start_time,$end_time='',$sort='asc'){

      $return = array();

      $startYearMonth = date('Ym',strtotime($start_time));
      $endYearMonth = $end_time?date('Ym',strtotime($end_time)):date('Ym');

      $yearMonth = $startYearMonth;
      $return[] = $yearMonth;
      while ($yearMonth<$endYearMonth){

         $yearMonth = yearMonthAddOne($yearMonth);
         $return[] = $yearMonth;
      }

      if($sort=='desc'){
         $return = array_reverse($return);
      }

      return $return;
   }
}