--写个……………………
select * 
from (select level rn 
from dual
connect by level<18)
where rn not in(3,4,6,8)

------解决方案--------------------
SQL code

[SYS@orcl] SQL>WITH xxx AS(
  2  SELECT 1  ID FROM DUAL UNION ALL
  3  SELECT 2  ID FROM DUAL UNION ALL
  4  SELECT 5  ID FROM DUAL UNION ALL
  5  SELECT 7  ID FROM DUAL UNION ALL
  6  SELECT 9  ID FROM DUAL UNION ALL
  7  SELECT 10 ID FROM DUAL UNION ALL
  8  SELECT 11 ID FROM DUAL UNION ALL
  9  SELECT 12 ID FROM DUAL UNION ALL
 10  SELECT 13 ID FROM DUAL UNION ALL
 11  SELECT 14 ID FROM DUAL UNION ALL
 12  SELECT 15 ID FROM DUAL UNION ALL
 13  SELECT 16 ID FROM DUAL UNION ALL
 14  SELECT 17 ID FROM DUAL)
 15  SELECT WM_CONCAT(DECODE(MIID, MAID, TO_CHAR(MAID), MIID || '-' || MAID))
 16    FROM (SELECT MIN(ID) MIID, MAX(ID) MAID
 17            FROM (SELECT ID, ID - DENSE_RANK() OVER(ORDER BY ID) ROW_ FROM XXX)
 18           GROUP BY ROW_
 19           ORDER BY MIID);

WM_CONCAT(DECODE(MIID,MAID,TO_CHAR(MAID),MIID||'-'||MAID))
--------------------------------------------
1-2,5,7,9-17

------解决方案--------------------
老题目了..
SQL code
with xxx as
 (select rownum id
    from dual
  connect by rownum < 18
  minus (select 3
          from dual
        union all
        select 4
          from dual
        union
        select 6
          from dual
        union
        select 8 from dual))
--以上是测试数据
select cast (wm_concat(id) as varchar2(4000)) id
  from (select case count(1)
                 when 1 then
                  to_char(min(id))
                 else
                  min(id) || '-' || max(id)
               end id
          from (select id from xxx order by id)
         group by rownum - id
         order by id)

------解决方案--------------------
SQL code
SELECT MIN(ID)||'-'||MAX(ID) AS gd FROM (
SELECT ID,ROWNUM rn FROM vnum ORDER BY ID)
GROUP BY ID-rn
ORDER BY gd;