我刚刚创建了一个表：

CREATE TABLE `table_test` (
`time` date NOT NULL,
`line_id` char(36) NOT NULL,
`location_id` char(36) NOT NULL,
`placement_id` char(36) NOT NULL,
`flight_id` char(36) NOT NULL,
`impressions` int(11) DEFAULT `0`,
PRIMARY KEY (`time`,`line_id`,`location_id`,`placement_id`,`flight_id`),
KEY `table_test_IDX` (`time`,`placement_id`,`line_id`,`impressions`) USING 
BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8

然后，当我尝试执行查询时：

SELECT 
  time,
  placement_id,
  line_id,
  SUM(impressions) AS totalImpress
FROM
  table_test
WHERE
  time BETWEEN '2017-11-01' AND '2017-11-30'
GROUP BY time , placement_id , line_id;

只花了0.28秒。
但当我试图执行时：

SELECT
  daily.`time`,
  daily.placement_id,
  daily.line_id,
  daily.totalImpress
FROM
(SELECT 
  time,
  placement_id,
  line_id,
  SUM(impressions) AS totalImpress
 FROM
  table_test
 WHERE
  time BETWEEN '2017-11-01' AND '2017-11-30'
 GROUP BY time , placement_id , line_id)
 daily

执行起来花了7秒多。
我做错什么了？
非常感谢。