jeigu kas nors nepatingetu pazhaisti...

CREATE TABLE IF NOT EXISTS `t1` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

INSERT INTO `t1` (`id`, `name`) VALUES
(1, 'vardas1'),
(2, 'vardas2');


CREATE TABLE IF NOT EXISTS `t2` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `t1_id` int(11) NOT NULL,
  `kaina` decimal(10,2) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;


INSERT INTO `t2` (`id`, `t1_id`, `kaina`) VALUES
(1, 1, '30.00'),
(2, 1, '20.00');

tai va, rezultate niekaip nepavyksta gauti pagal si pavyzdi, kad:
vardas1 sum(kaina) = 50, o vardas2 sum(kaina) = 0