mysql 5.7 order by group by 不能达到预期结果



DROP TABLE IF EXISTS `s_score`;
CREATE TABLE `s_score` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL DEFAULT '',
  `subject` varchar(255) NOT NULL DEFAULT '',
  `score` float NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `s_score` (`id`, `name`, `subject`, `score`) VALUES
(1,	'allen',	'语文',	60),
(2,	'allen',	'数学',	75),
(3,	'allen',	'英语',	78),
(4,	'tang',	'语文',	67),
(5,	'tang',	'数学',	78),
(6,	'tang',	'英语',	88),
(7,	'lily',	'语文',	98),
(8,	'lily',	'数学',	87),
(9,	'lily',	'英语',	70);

查询每个人最优结果，结果包含 id,name,subject,score列。
select a.name,a.subject,a.score from (select id,name,subject,score from s_score order by score desc limit 1000) as a
group by a.name