sql에서 동일값 확인 후 내용 뽑기

<?
        $write_table = $g5['write_prefix'] . $bo_table;
        $sum_count = "0";
        $sql = "
            select a.mb_id, b.mb_name, count(*) as cnt , sum(a.wr_31) as tot        
              from {$write_table} a
                       left outer join {$g5['member_table']} b on a.mb_id = b.mb_id 
             where wr_29 between '{$stx1}' and '{$stx2}'
             group by a.mb_id, b.mb_name ORDER BY tot DESC
        ";
        $result = sql_query($sql);
        while ($row = sql_fetch_array($result)) {
        $sum_count ++
        ?>

        <tr>
            <td class="td_c"><?php echo $sum_count ?>위</td>
            <td class="td_c"><?php echo $row['mb_name'] ?></td>
            <td class="td_c"><?php echo $row['cnt'] ?> 명</td>
            <td class="td_r"><?php echo number_format($row['tot']) ?>원</td>
        <?php } ?>