mysql语句，按照年，月，或者日分组

table_name 为表名
time 为日期字段

1、按月分组：

select month(FROM_UNIXTIME(time)) 
from table_name 
group by month(FROM_UNIXTIME(time))

2、按年月分组：

select DATE_FORMAT(FROM_UNIXTIME(time),"%Y-%m") 
from table_name 
group by DATE_FORMAT(FROM_UNIXTIME(time),"%Y-%m")

或者：

select FROM_UNIXTIME(time,"%Y-%m") 
from table_name 
group by FROM_UNIXTIME(time,"%Y-%m")

3、按年月日分组：

select DATE_FORMAT(FROM_UNIXTIME(time),"%Y-%m-%d") 
from table_name 
group by DATE_FORMAT(FROM_UNIXTIME(time),"%Y-%m-%d")

或者：

select FROM_UNIXTIME(time,"%Y-%m-%d") 
from table_name 
group by FROM_UNIXTIME(time,"%Y-%m-%d")