select mm,
nvl(quantity,0)
from(select rownum mm from dual connect by rownum<=12)t1,
(select to_char(time,'mm') mm,count(name) quantity from tb
where to_char(time,'YYYY')='2010' 
group by to_char(time,'mm'))t2
where t1.mm=t2.mm(+)
order by t1.mm

------解决方案--------------------
1.  
select to_char(time,'yyyy-mm') mm,count(name) quantity from tb
where to_char(time,'YYYY')='2010'  
group by to_char(time,'mm')
order by to_char(time,'mm')  

2.
"select rownum mm from dual connect by rownum<=12" 这句算画蛇添足吗？

------解决方案--------------------
group by你的时间，是组查询

------解决方案--------------------
SQL code

select to_char(time,'yyyymm'),count(name) from your_table
where to_char(time,'YYYY')='2010'  
group by to_char(time,'yyyymm')
order by to_char(time,'yyyymm')

------解决方案--------------------
我建了一个简单的表，然后再里面插入了几条数据如下：
create table s(name varchar2(10),time date);
insert into  s values('tt',to_date ( '2010-02-02' , 'YYYY-MM-DD' ) );

insert into  s values('tt',to_date ( '2010-01-02' , 'YYYY-MM-DD' ) );
insert into  s values('by',to_date ( '2010-03-02' , 'YYYY-MM-DD' ) );
insert into  s values('gy',to_date ( '2010-04-02' , 'YYYY-MM-DD' ) );
insert into  s values('ey',to_date ( '2010-05-02' , 'YYYY-MM-DD' ) );

insert into  s values('tt',to_date ( '2010-01-02' , 'YYYY-MM-DD' ) );
insert into  s values('by',to_date ( '2010-03-02' , 'YYYY-MM-DD' ) );
insert into  s values('gy',to_date ( '2010-04-02' , 'YYYY-MM-DD' ) );
insert into  s values('ey',to_date ( '2010-05-02' , 'YYYY-MM-DD' ) );
然后执行的查询语句是：
select to_char(time, 'mm'), name, count(1)
 from s
  where to_char(time, 'yyyy') = 2010
  group by to_char(time, 'mm'), name;

结果就出来了，希望对你有帮助。

------解决方案--------------------
select to_char(time,'yyyymm'),count(distinct name) from tabl1  
where to_char(time,'yyyy')='2010'
group by  to_char(time,'yyyymm')

------解决方案--------------------
实测，请参考：


------解决方案--------------------
select to_char(time,'yyyy-mm') mm,count(name) quantity from tb
where to_char(time,'YYYY')='2010' 
group by to_char(time,'mm')
order by to_char(time,'mm') 


------解决方案--------------------
探讨


实测，请参考：


------解决方案--------------------
SQL code

select to_char(time,'yyyy-mm')as  mm,count(name)  from tb_name
where to_char(time,'YYYY')='2010'   
group by to_char(time,'mm')
order by to_char(time,'mm')  
--
--或者
select to_char(time,'yyyy-mm')as  mm,count(name)  from tb_name
where  to_char(time,'YYYY')='2010'   
group by to_char(time,'yyyy-mm')
order by to_char(time,'yyyy-mm')