Помогите с запросиком

ID_VZNOSI  ID_FIRM  ID_ACCOUNT    DATE_SP         SUMA
----------   -------    ---------- --------      -------
1084            414       2      16.03.04       250 
1086            81        1      14.01.04       120
1087            27        1      16.02.04       129,6
1088            60        1      16.02.04       129,6
1089            228       3      18.03.04       129,6

ID_FIRM             Cума по счету 1   Cума по счету 2 ....
---------- 		----------
        13              96		        ...
        14              359                     ...
        20              3653,76
        21              864
        22              14762,8

select id_firm, (select sum(suma) from vznosi xxx where id_account=1 and xxx.id_firm=yyy.id_firm)  Schet_1,
select id_firm, (select sum(suma) from vznosi xxx where id_account=2 and xxx.id_firm=yyy.id_firm)  Schet_2,
....
select id_firm, (select sum(suma) from vznosi xxx where id_account=13 and xxx.id_firm=yyy.id_firm)  Schet_13
from vznosi yyy
group by id_firm;

SELECT id_firm,
       sum(decode(id_account,1,suma,0)) as Schet_1,
       sum(decode(id_account,2,suma,0)) as Schet_2,
       sum(decode(id_account,3,suma,0)) as Schet_3,
       ....
       sum(decode(id_account,12,suma,0)) as Schet_12,
       sum(decode(id_account,13,suma,0)) as Schet_13
  FROM vznosi
  GROUP BY id_firm