DROP FUNCTION IF EXISTS GetNextBelegnr;

DELIMITER $$
CREATE FUNCTION `GetNextBelegnr`(addToCount INT) RETURNS int(11)
BEGIN
  DECLARE COUNT_FOUND INTEGER DEFAULT 1;

    SELECT count INTO COUNT_FOUND FROM callcount WHERE OID = 1;
    UPDATE callcount SET Count = Count + addToCount WHERE OID = 1;
  RETURN COUNT_FOUND;
RETURN -1;
END$$
DELIMITER ;