CREATE TABLE `table1` (
  `id` int(11) DEFAULT NULL,
  `key` int(11) DEFAULT NULL,
  `value` varchar(20) DEFAULT NULL,
  `dt` datetime DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `table1` VALUES 
('1', '1', '111', '2016-02-01 11:05:09'), 
('2', '1', '112', '2016-02-02 11:05:35'), 
('3', '1', '113', '2016-02-03 11:05:49'), 
('4', '1', '114', '2016-02-10 11:06:05'), 
('5', '1', '115', '2016-02-13 11:06:16'), 
('6', '2', '211', '2016-02-02 11:07:38'), 
('7', '2', '212', '2016-02-05 11:07:52'), 
('8', '2', '213', '2016-02-07 11:08:07'), 
('9', '2', '214', '2016-02-09 11:08:19'), 
('10', '2', '215', '2016-02-12 11:08:33');

CREATE TABLE `table2` (
  `key` int(11) DEFAULT NULL,
  `value` varchar(20) DEFAULT NULL,
  `from_date` datetime DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `table2` VALUES 
('1', 'v1', '2016-02-01 00:00:00'), 
('1', 'v2', '2016-02-03 11:07:06'), 
('1', 'v3', '2016-02-10 11:07:18'), 
('2', 'v2_1', '2016-02-03 11:08:57'), 
('2', 'v2_2', '2016-02-06 11:09:10'), 
('2', 'v2_3', '2016-02-10 11:09:25');