oracle 实现按周,月,季度,年查询统计数据

oracle 实现按周,月,季度,年查询统计数据

select to_char(to_date('20090101','yyyymmdd')+rownum+7,'iw') column_name from dual connect by rownum<=to_date('20111201','yyyymmdd')-to_date('20090101','yyyymmdd')

//按自然周统计 
select to_char(date,'iw'),sum() 
from 
where 
group by to_char(date,'iw') 

//按自然月统计 
select to_char(date,'mm'),sum() 
from 
where 
group by to_char(date,'mm') 

//按季统计 
select to_char(date,'q'),sum() 
from 
where 
group by to_char(date,'q') 

//按年统计 
select to_char(date,'yyyy'),sum() 
from 
where 
group by to_char(date,'yyyy')