SELECT id,
      ven,
	  CONCAT( ven, IF( RIGHT(ven,1) REGEXP ('^[0-9]'),'0', '' ) )  AS vif,
      CONCAT( REPEAT( 0, 6 - LENGTH((SELECT vif))), (SELECT vif) ) AS ved
FROM den ORDER BY ved ASC ;

CREATE TABLE `den` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `ven` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `ven_UNIQUE` (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;


INSERT INTO `den` VALUES (1,'1a'),(2,'1b'),(3,'2a'),(4,'2b'),(5,'2c'),(6,'14a'),(7,'14c'),(8,'20');