mysql 统计

每周：

select count(*) as cnt,week(editdate) as weekflg from projects where year(editdate)=2007 group by weekflg

每月：

select count(*) as cnt,month(editdate) as monthflg from projects where year(editdate)=2007 group by monthflg

每天：

select count(*) as cnt from projects group by date(editdate)

Demo：

（thinkphp框架）

M('UserCourseSection')
    ->field('count(*) as nums,left(last_time, 10) as time')
    ->group('date(last_time)')
    ->order('last_time desc')
    ->select();

last_time 为数据库日期字段