此处不允许序号

【急】此处不允许序号？

  insert into
      archive_statistics
    select
      archive_statistics_seq.nextval,
      '2014-11',
      '11',
      sum(first_open),
      sum(curr_open),
      sum(curr_debt),
      sum(total_space),
      sum(total_cost)
    from 
    (
      select
        count(va_id) first_open,
        0 curr_open,
        0 curr_debt,
        0 total_space,
        0 total_cost
      from
        archive_log
      where
        val_opt_type = 0
        and to_char(val_create_time, 'yyyy-mm-dd') = '2014-11-30'
        union all
      select
        0 first_open,
        decode(val_opt_after_status, 0, 1, 0) curr_open,
        decode(val_opt_after_status, 1, 1, 0) curr_debt,
        0 total_space,
        0 total_cost
      from
        archive_log val, 
        (
          select
            va_id,
            max(val_id) val_id
from
archive_log
where
to_char(val_create_time, 'yyyy-mm-dd') = '2014-11-30'
group by
va_id
) tab
where
val.val_id = tab.val_id
union all
select
0 first_open,
0 curr_open,
0 curr_debt,
decode(vacl_last_status, 0, vacl_all_space, 1, vacl_all_space, 2, vacl_all_space, 0) total_space,
decode(vacl_last_status, 0, vacl_total_cost, 1, vacl_total_cost, 0) total_cost
from
archive_cost_log
where
to_char(vacl_create_time, 'yyyy-mm-dd') =  '2014-11-30'    
        ) 

一运行报ORA-02287错误：此处不允许序号，nextval之类的头一次接触，改半天也没弄成，具体怎么改呢，急啊，今天得改完。。。。。。100分不够再加！！谢了
------解决思路----------------------
序列不能用在分组查询当中
在外面再嵌套一层
就是说，把
select seq1.nextval,sum(a) from tab
改成
select seq1.nextval,sum_a from (
  select sum(a) sum_a from tab)
的形式
------解决思路----------------------
都解决完了啊，呵呵，走鸟