统计相似记录中的记录百分比

我有T桌:

ID    Type
----  ----
1     a
1     b
2     a
2     a
3     b

以及第一个表-n中ID名称的表:

ID    Name
----  ----
1     name1
2     name2
3     name3

我需要在pl/sql中查询相同ID(按ID分组)的所有类型中类型出现的计数百分比。

结果必须是:

Name   a%   b%     row
---    ----  ---   ---
name1  50    50   1
name2  100   0    2
name3  0     100  3

我尝试过:

select 
    n.name,
    a.perc as "a%",
    b.perc as "b%",
    row_number() over (
        order by name asc
    ) mf_rownumber
from n n
left join
    (select 
        id,
        round(100 * (count(*) / sum(count(*)) over ()), 2) perc
    from t
    where (type = 'a')
    group by id) a
    on a.id = n.id
left join
    (select 
        id,
        round(100 * (count(*) / sum(count(*)) over ()), 2) perc
    from t
    where (type = 'b')
    group by id) b
    on b.id = n.id;

我得到的是所有行中每种类型的百分比:

Name    a%   b%     row
---     ----  ---   ---
name1   20    20   1
name2   40    0    2
name3   0     20   3

但我需要计算相同ID边界中的所有内容,而不是所有行。