Mysql效率问题
表
CREATE TABLE `ch1` (
`id` int(10) unsigned zerofill NOT NULL AUTO_INCREMENT,
`no` int(10) unsigned DEFAULT NULL,
`dtime` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
)
查询语句 select sum(no) as number,dtime as date from ch1 group by month(dtime)
数据大约1000w条记录,需要40秒,感觉太慢了,有什么解决办法?