/**
  * 转化率走势
  * @param int $stationid 车站id
  * @param date $sdate    起始日期
  * @param date $edate    结束日期
  */
 public function UserRate($stationid, $sdate, $edate)
 {
     $reg_sdate = date('Y_m_d', strtotime($sdate));
     if (!$edate) {
         $reg_where = " and date = '{$reg_sdate}'";
         $connect_where = " and date = '{$sdate}'";
     } else {
         $reg_edate = date('Y_m_d', strtotime($edate));
         $reg_where = " and date BETWEEN '{$reg_sdate}' AND '{$reg_edate}'";
         $connect_where = " and date BETWEEN '{$sdate}' AND '{$edate}'";
     }
     $obj = new Psys_StationRule();
     return $obj->UserRate($stationid, $reg_where, $connect_where);
 }