请问一个计算百分比的有关问题

请教一个计算百分比的问题
数据如下：

类别 品名 数量
A 鸭脖 25.5
A 鸡爪 82
B 脉动 26
A 香肠 12
B 加多宝 22


需求是我要得到A类中每个品名占自己类别数量的百分比SQL该如何写？

想查询得到
品名 数量 比例
鸭脖 25.5 21.34%
鸡爪 82 68.62%
香肠 12 10.04%
脉动 26 54.17%
加多宝 22 45.83%



[解决办法]
sql写成这样了 如果非要小类大类统计 考虑分开统计了union all合并吧

SQL code

with t1 as(     select 'C' c1,'A' c2,'鸭脖' c3,25.5 c4 from dual      union all     select 'C' c1,'A' c2,'鸡爪' c3,82 c4 from dual      union all     select 'C' c1,'B' c2,'脉动' c3,26 c4 from dual      union all     select 'C' c1,'A' c2,'香肠' c3,12 c4 from dual      union all     select 'C' c1,'B' c2,'加多宝' c3,22 c4 from dual      union all     select 'D' c1,'E' c2,'牙刷' c3,36 c4 from dual      union all     select 'D' c1,'E' c2,'毛巾' c3,22 c4 from dual )select c1,c2,c3,c4,       round(c4/sum(c4) over(partition by c1,c2),4)*100||'%' c5,       round(c4/sum(c4) over(partition by c1),4)*100||'%' c6from t1     c1    c2    c3    c4     c5     c6-----------------------1    C    A    鸭脖    25.5    21.34%    15.22%2    C    A    鸡爪    82    68.62%    48.96%3    C    A    香肠    12    10.04%    7.16%4    C    B    加多宝    22    45.83%    13.13%5    C    B    脉动    26    54.17%    15.52%6    D    E    毛巾    22    37.93%    37.93%7    D    E    牙刷    36    62.07%    62.07%