CURSOR curs IS
  SELECT cust_id--,COUNT(cust_id) AS num_ocurrences
  FROM trab.sales
  GROUP BY cust_id
  HAVING ( COUNT(cust_id)>=1 )
  ORDER BY cust_id;

  last_sale DATE;

BEGIN
  FOR cs IN curs
  LOOP
    SELECT MAX(sale_date)INTO last_date FROM trab.sales s WHERE s.cust_id= cs.cust_id;
    UPDATE indw.CLIENTS aux_t SET aux_t.CLIENT_LAST_BUY = last_date
    WHERE aux_t.CLIENT_ID_SRC = cs.CUST_ID;
  END LOOP;
END;