php按某个字段排序，怎么取某个id的名次？

[奔波在生活路上]

   $sql ="select * from user_active as a left join user_integral as b on a.uid = b.uid where a.uid='".$id."'";
                $resz=mysql_query($sql);
                $userinfo = mysql_fetch_array($resz, MYSQL_ASSOC);
                //print_r($userinfo);
                if ($userinfo) {     
                    $huodong=$userinfo['activeNum'];
                    $userid=$userinfo['uid'];
                    //获取所有用户倒叙排序
                $sqln ="select * from user_active order by activeNum desc ";
                $resn=mysql_query($sqln);
                $userp = mysql_fetch_array($resn, MYSQL_ASSOC);
             $i = 0;
             foreach($userp as $val){
                 $i++;
                 $data[$val['uid']]['click'] = $i;
                 $data[$val['uid']]['uid'] = $val['uid'];
                 $paiming=$data[$userid]['click'];
                 print_r($paiming);

                }
                   $renshu=$userinfo['p_number'];
                   $zongfen=$userinfo['integral'];
                   $zongren=$userinfo['p_num'];
                } else {
                  echo "没有您的数据"; 
                  exit;
                } 
mysql_close($connection);

前面有取到用户ID 然后 我这里查询所有用户根据分数倒叙
根据activeNum 这个分数来排序，分数最高就是第一，分数第二就是第二名
我这里用foreach来取值，赋值$paiming,但是老是有问题。应该怎么做，求大大帮忙