How to generate fibonacci series in Oracle.

Way 1:

with data as (select level levels from dual
                    connect by level <= &how_may_rows)
select f from data
                    model dimension by (levels)
                    measures ( 0 f)
         rules (   f[1] = 0 , f[2] = 1 , f[levels>2]=f[cv(levels)-2]+f[cv(levels)-1]
);
Enter value for how_may_rows: 10
old   2:                       connect by level <= &how_may_rows)
new   2:                       connect by level <= 10)

        F
----------
        0
        1
        1
        2
        3
        5
        8
       13
       21
       34

10 rows selected.

Way 2:

Just a variant of way 1,

SQL> select s seq from dual
  model return all rows
  dimension by ( 0 d ) measures ( 0 s )
  rules iterate (&n) (
  s[iteration_number ] = decode(
  iteration_number, 0, 0, 1, 1, s[iteration_number-2]
  ) + nvl(s[iteration_number-1],0)
  )
  /
Enter value for n: 8
old   4:     rules iterate (&n) (
new   4:     rules iterate (8) (

     SEQ
----------
       0
       1
       1
       2
       3
       5
       8
      13

8 rows selected.

Way 3: Using Math Formula

SQL> select round ((power ((1 + sqrt (5)) / 2, level - 1) - power ((1 - sqrt (5)) / 2, level - 1)) / sqrt (5)) fib
     from dual
connect by level <=&n;
Enter value for n: 8
old   3: connect by level <=&n
new   3: connect by level <=8

      FIB
----------
        0
        1
        1
        2
        3
        5
        8
       13

8 rows selected.