oracle分组查询（某年12月的数据和每年每月的数据）
//查询某年1-12月的数据
select to_char(createdate,'yyyy-mm') 月份,count(*) 数量 from cms_news where ispub='1'
and createdate between to_date('2014-01','yyyy-mm') and to_date('2014-12','yyyy-mm') group by to_char(createdate,'yyyy-mm') order by to_char(createdate,'yyyy-mm');
//查询每年每月的数据
select to_char(createdate,'yyyy-mm') 月份,count(*) 数量 from cms_news group by to_char(createdate,'yyyy-mm') order by to_char(createdate,'yyyy-mm');