Sql query to list 1..25 numbers.

Question

Hi all,
How could I write a query (not pl/sql) to generate a series fo numbers.
Don't take any dependent tables, meant if i have a table with more than 100 rows then by writing "select rownum from mytable where rownum<101; will gives the results what i required.
But I am looking for a query which is indipendet of other tables , ofcourse you can use DUAL or any standard functions.
Thanks in advance,
Khaleel.

Answer 1

Ultimately, queries can only be run against tables. Of course, Oracle has developed somewhat, and those "tables" can now be CAST arrays or in-line SELECT statements as well as views, but there has to be something in the FROM clause that is either a table or somehow maps to a table.
Your best bet for a schema independent solution is to use ALL_OBJECTS, as even in the meanest system that should offer every user a few thousand rows.
SELECT rownum my_number FROM all_objects WHERE rownum < 26;You can't do it a simple PL/SQL function, because the function gets called for each row.
SQL> create or replace function my_num return number is
  2  i number := 0;
  3  begin
  4  i := i+1;
  5  return i;
  6  end;
  7  /
Function created.
SQL> select my_num from  all_objects where rownum < 5
  2  /
    MY_NUM
         1
         1
         1
         1
SQL>
[/code]
However, packages don't re-initialise variables with each call, sp you could do this:
[code]
SQL> CREATE OR REPLACE PACKAGE num_test AS
  2    FUNCTION my_num return NUMBER;
  3  END;
  4  /
Package created.
SQL> CREATE OR REPLACE PACKAGE BODY num_test AS
  2   i NUMBER;
  3   FUNCTION my_num return NUMBER IS
  4   BEGIN
  5      i:=i+1;
  6      RETURN i;
  7      END;
  8  BEGIN
  9   i:=0;
10  END;
11  /
Package body created.
SQL> select num_test.my_num from  all_objects where rownum < 5
  2  /
    MY_NUM
         1
         2
         3
         4
SQL>
[/code]
Bear in mind that if you go down this route you will need to add a method to re-initialise the count, because the variables retain their value within the session:
[code]
SQL> select num_test.my_num from  all_source where rownum < 5
  2  /
    MY_NUM
         5
         6
         7
         8
SQL>
[/code]
Rgds, APC