게시판 그룹 추출할때 날짜순으로 정렬이 궁금합니다. 채택완료

그룹별 추출을 날짜순으로 변경하고 싶습니다.
여기저기 검색해서 수정해 봤는데 도저히 안되서...질문드립니다.
쿼리쪽으로는 많이 부족해서 지식의 한계를 느껴서 올려봅니다. ㅠㅠ
고수님들 답변부탁드립니다!

// 최신글 추출
// $cache_time 캐시 갱신시간
function latest_group($skin_dir='', $gr_id, $rows=10, $subject_len=40, $cache_time=1, $options='')

{
    global $g5;

    if (!$skin_dir) $skin_dir = 'basic';

    if(preg_match('#^theme/(.+)$#', $skin_dir, $match)) {
        if (G5_IS_MOBILE) {
            $latest_skin_path = G5_THEME_MOBILE_PATH.'/'.G5_SKIN_DIR.'/latest/'.$match[1];
            if(!is_dir($latest_skin_path))
                $latest_skin_path = G5_THEME_PATH.'/'.G5_SKIN_DIR.'/latest/'.$match[1];
            $latest_skin_url = str_replace(G5_PATH, G5_URL, $latest_skin_path);
        } else {
            $latest_skin_path = G5_THEME_PATH.'/'.G5_SKIN_DIR.'/latest/'.$match[1];
            $latest_skin_url = str_replace(G5_PATH, G5_URL, $latest_skin_path);
        }
        $skin_dir = $match[1];
    } else {
        if(G5_IS_MOBILE) {
            $latest_skin_path = G5_MOBILE_PATH.'/'.G5_SKIN_DIR.'/latest/'.$skin_dir;
            $latest_skin_url  = G5_MOBILE_URL.'/'.G5_SKIN_DIR.'/latest/'.$skin_dir;
        } else {
            $latest_skin_path = G5_SKIN_PATH.'/latest/'.$skin_dir;
            $latest_skin_url  = G5_SKIN_URL.'/latest/'.$skin_dir;
        }
    }

    $cache_fwrite = false;
    if(G5_USE_CACHE) {
        $cache_file = G5_DATA_PATH."/cache/latest-group-{$gr_id}-{$skin_dir}-{$rows}-{$subject_len}.php";

        if(!file_exists($cache_file)) {
            $cache_fwrite = true;
        } else {
            if($cache_time > 0) {
                $filetime = filemtime($cache_file);
                if($filetime && $filetime < (G5_SERVER_TIME - 3600 * $cache_time)) {
                    @unlink($cache_file);
                    $cache_fwrite = true;
                }
            }

            if(!$cache_fwrite)
                include($cache_file);
        }
    }

    if(!G5_USE_CACHE || $cache_fwrite) {
        $list = array();
        $sql_common = " from {$g5['board_new_table']} a, {$g5['board_table']} b, {$g5['group_table']} c where a.bo_table = b.bo_table and b.gr_id = c.gr_id and b.bo_use_search = 1 ";
        $sql_common .= " and b.gr_id = '$gr_id' ";
        // $sql_common .= " and a.bo_table not in ('aaaa', 'bbbb') ";
        $sql_common .= " and a.wr_id = a.wr_parent ";
        $sql_order = " order by a.bn_id desc ";
        $sql = " select a.*, b.bo_subject, c.gr_subject, c.gr_id {$sql_common} {$sql_order} limit 0, {$rows}";
  $result = sql_query($sql);

  for ($i=0; $row=sql_fetch_array($result); $i++) {

   $sql = " select * from {$g5['board_table']} where bo_table = '{$row['bo_table']}' ";
   $board = sql_fetch($sql);
   $gr_subject = $row['gr_subject'];

   $tmp_write_table = $g5['write_prefix'] . $row['bo_table'];
   $row2 = sql_fetch(" select * from {$tmp_write_table} where wr_id = '{$row['wr_id']}' ");

   $list[$i] = $row2;
   $list[$i] = get_list($row2, $board, $latest_skin_url, $subject_len);
   $list[$i]['bo_subject'] = $row['bo_subject'];
   $list[$i]['bo_table'] = $row['bo_table'];
  }

        if($cache_fwrite) {
            $handle = fopen($cache_file, 'w');
            $cache_content = "<?php\nif (!defined('_GNUBOARD_')) exit;\n\$gr_subject='".$gr_subject."';\n\$list=".var_export($list, true)."?>";
            fwrite($handle, $cache_content);
            fclose($handle);
        }
    }

    ob_start();
    include $latest_skin_path.'/latest.skin.php';
    $content = ob_get_contents();
    ob_end_clean();

    return $content;
}