[ORACLE SQL] Combination Calculation

You replace the string 'ALI' with any type you prefer and use to calculate combination of strings by letters.

WITH got_a_char AS

(SELECT 'ALI' AS txt, substr('ALI', LEVEL, 1) AS a_char, LEVEL AS n

    FROM dual

  CONNECT BY LEVEL <= length('ALI'))

SELECT DISTINCT REPLACE(sys_connect_by_path(a_char, '~~'), '~~') AS perm

  FROM got_a_char

WHERE LEVEL = length(txt)

CONNECT BY nocycle txt = PRIOR txt

       AND n != PRIOR n;

Result:

LIA

ILA

ALI

IAL

LAI

AIL