最近由于要做报表，在一张表中有一个字段为date类型，现在想要在一段时间内（比如一年）能够按照时间段分组查询记录总和，比如我要能够查询2007年到2009年间按月份分组记录条数统计，网上提示用 group by to_char(date_column, 'yyy-mm'),构造如下sql语句：
select count(*), s.create_date as date_split
from sample s
where s.create_date between '2007-01' and '2009-12'
group by to_char(date_split, 'yyy-mm');
但是，我不只是要能按月份来分组，还要求能够按周和季度来分组，这种查询语句怎么构造呢，网上似乎没有这方面资料，望大虾教我，小弟不胜感激！
季度的有个笨办法：
SQL> select to_char(b,'YYYY-MM') from table1;
TO_CHAR(B,'YYY
--------------
2009-09
2009-09
2009-09
2008-11
2008-11
2008-09
2009-05
2009-12
2009-12
已选择9行。
SQL> select to_char(b,'YYYY'),sum(decode(to_char(b,'MM'),'01',1,'02',1,'03',1,0)) as one,
2 sum(decode(to_char(b,'MM'),'04',1,'05',1,'06',1,0)) as two,
3 sum(decode(to_char(b,'MM'),'07',1,'08',1,'09',1,0)) as three,
4 sum(decode(to_char(b,'MM'),'10',1,'11',1,'12',1,0)) as four from table1
5 group by to_cha
private static final String URL = "jdbc:oracle:thin:@localhost:1521:orcl";
private static final String USERNAME = "sys";
private static final String PASSWORD = "s ......
