PHP 返回近7天 本月 上月日期

 <?php
 /**
  * 返回近7天，本月，上月数据
  * 不计当天（展示后台数据专用）
  */
 function weekMonthLastMonth($search_date = 'week') {

     switch($search_date)
     {
         case 'week' : // 近7天
             $start_date = date ("Y-m-d", strtotime("-7 days"));
             $end_date = date ("Y-m-d", strtotime("-1 days"));
             break;
         case 'month' : // 本月
             $start_date = date ("Y-m-01", strtotime("-1 days"));
             $end_date = date ("Y-m-d", strtotime("-1 days"));
             break;
         case 'last_month' : // 上月
             $search_time = strtotime ("-1 month");
             $start_date = date ("Y-m-01", $search_time);
             $end_date = date ('Y-m-d', strtotime("$start_date +1 month -1 day"));
             break;
     }
     return array($start_date, $end_date);
 }

 echo print_r(weekMonthLastMonth('week'), true);
 echo print_r(weekMonthLastMonth('month'), true);
 echo print_r(weekMonthLastMonth('last_month'), true);