with tt as(
  select 1 f1,'00000001' f2 from dual union all
  select 1 f1,'00000002' f2 from dual union all
  select 1 f1,'00000003' f2 from dual union all
  select 1 f1,'00000004' f2 from dual union all
  select 1 f1,'00000005' f2 from dual union all
  select 1 f1,'00000007' f2 from dual union all
  select 1 f1,'00000008' f2 from dual union all
  select 1 f1,'00000009' f2 from dual union all
  select 2 f1,'00000120' f2 from dual union all
  select 2 f1,'00000121' f2 from dual union all
  select 2 f1,'00000122' f2 from dual union all
  select 2 f1,'00000124' f2 from dual union all
  select 2 f1,'00000125' f2 from dual)

select f1,min(f2)||','||max(f2) f2 from tt t
start with not exists(select 1 from tt where f1=t.f1 and f2=to_char(t.f2-1,'fm00000000'))
connect by prior f1=f1
and f2=prior to_char(f2+1,'fm00000000')
group by f1,rownum-level

------解决方案--------------------
SQL code
--写一个
with tt as(
  select 1 f1,'00000001' f2 from dual union all
  select 1 f1,'00000002' f2 from dual union all
  select 1 f1,'00000003' f2 from dual union all
  select 1 f1,'00000004' f2 from dual union all
  select 1 f1,'00000005' f2 from dual union all
  select 1 f1,'00000007' f2 from dual union all
  select 1 f1,'00000008' f2 from dual union all
  select 1 f1,'00000009' f2 from dual union all
  select 2 f1,'00000120' f2 from dual union all
  select 2 f1,'00000121' f2 from dual union all
  select 2 f1,'00000122' f2 from dual union all
  select 2 f1,'00000124' f2 from dual union all
  select 2 f1,'00000125' f2 from dual)
SELECT f1, MIN(f2) || ',' || MAX(f2)
  FROM (SELECT f2 - rownum gn, a.* FROM (SELECT * FROM tt ORDER BY f2) a) b
 GROUP BY f1, b.gn
 ORDER BY f1