I need a resultset with 10 rows from dual

Question

Which is the easiest SELECT I have to write, when the question is: "I need a resultset with 10 rows from dual"
one solution is
SELECT 'X' FROM EMP WHERE ROWNUM <= 10;
problem: if emp has fewer than 10 rows, I have an incorrect resultset
another problem: if I need 1000 and not 10 dummy-rows, than is emp definitely the wrong way, because the default-emp table has only 14 rows.
Is there an easy generic solution for this problem? If I need only one row, Oracle has the workaround with the DUAL-table.

Answer 1

What about this new method (dedicated by me to this great FORUM!). It is easy to use, easy to understand, and very fast:
SQL> set echo on
SQL> set timing on
SQL> select rownum
  2    from all_objects
  3   where rownum <=10;
    ROWNUM
         1
         2
         3
         4
         5
         6
         7
         8
         9
        10
10 rows selected.
Elapsed: 00:00:00.00
SQL> select COUNT(rownum)
  2    from all_objects
  3   where rownum <=1000;
COUNT(ROWNUM)
         1000
Elapsed: 00:00:00.00
SQL> with r1000
  2  as (select rownum
  3        from all_objects
  4        where rownum <=1000)
  5  select count(rownum)
  6    from r1000, r1000
  7   where rownum <= 1000000;
COUNT(ROWNUM)
      1000000
Elapsed: 00:00:00.05 -- !for 1 million numbers!
SQL> with r1000
  2  as (select rownum
  3        from all_objects
  4        where rownum <=1000)
  5  select count(rownum)
  6    from r1000, r1000, r1000
  7   where rownum <= 10000000;
COUNT(ROWNUM)
     10000000
Elapsed: 00:00:04.09  -- !for 10 millions numbers!