WITH obmedzenci (id_obmedzitel, id_obmedzenec) AS (
  SELECT id_otec, id
  FROM obmedzenia
  WHERE id_otec NOT IN (SELECT id_hodnota2 FROM obmedzenia)
  
  UNION ALL

  SELECT otec.id, dieta.id
  FROM potomkovia otec, clen dieta
  WHERE otec.id_potomok = dieta.id_otec
)
SELECT predok.id, predok.meno, potomok.id, potomok.meno
FROM potomkovia p, clen predok, clen potomok
WHERE predok.id = p.id AND potomok.id = p.id_potomok
ORDER BY 1, 2