CREATE OR REPLACE FUNCTION permute(lst) as table (
  WITH RECURSIVE permute(perm, remaining) as (
    -- base case
    SELECT
        [] as perm,
        lst as remaining
    UNION ALL
    -- recursive case: add one element from remaining to perm and remove it from remaining
    SELECT
        (perm || [element]) AS perm,
         (remaining[1:i-1] || remaining[i+1:]) AS remaining
    FROM (select *, unnest(remaining) AS element, generate_subscripts(remaining,1) as i
          FROM permute)
  )
  SELECT perm
  FROM permute
  WHERE length(remaining) = 0
);