每月的数据:select * from table t where date_format(‘2015-01-01’,'%Y-%m') = date_format(kh_createtime,'%Y-%m');
每周的数据:select * from table t where (select date_add(date('2015-01-01'),INTERVAL -weekday('2015-01-01') day)) <= date_format(field,'%Y-%m-%d')
and date_format(field,'%Y-%m-%d') <= (select date_add(date('2015-01-01'),INTERVAL -weekday('2015-01-01')+6 day))