SQL> ed
Wrote file afiedt.buf

  1  select t.*,rownum,mod(rownum,3) m from
  2   (select ename from emp e ) t --селекта, возвращающего таблицу
  3  where rownum<10
  4* order by mod(rownum-1,3),rownum
SQL> /

ENAME          ROWNUM          M
---------- ---------- ----------
SMITH               1          1
JONES               4          1
CLARK               7          1
ALLEN               2          2
MARTIN              5          2
SCOTT               8          2
WARD                3          0
BLAKE               6          0
KING                9          0

9 rows selected.

SQL>