trinitry3

  1) This is not really a temporary table in the traditional
     sense; you're creating a real table and then dropping it.
     This has problems with concurrency (you can't have two
     "real" tables with the same name), among other issues.
  2) Temporary tables in Postgres suck because they bloat
     the catalogs.  Creating temporary tables regularly is
     better avoided.
  3) There's no real need to create a table of any kind.  A
     regular VALUES would do.  (Though you might have to encode
     some type information into the query.)

    SELECT u.user, i.text
    FROM users u,
    LATERAL (SELECT * FROM items WHERE items.user = u.user ORDER BY items.pos DESC LIMIT 3) i;