我正在尝试在SQL Server 2008 R2中做一些交叉表。那部分还好，但是，如果我尝试获取每个单元格的百分比，就会遇到问题。

这是一个提炼的用例：一项调查，人们在其中给出自己喜欢的颜色和喜欢的水果。我想知道有多少喜欢给定的水果和给定的颜色：

with survey as (
    select 'banana' fav_fruit, 'yellow' fav_color
     union select 'banana', 'red'
     union select 'apple', 'yellow'
     union select 'grape', 'red'
     union select 'apple', 'blue'
     union select 'orange', 'purple'
     union select 'pomegranate', 'green'
)
select
    s.fav_color, 
    sum(case 
          when s.fav_fruit = 'banana' then 1
          else 0
        end) as banana, 
    sum(case 
           when s.fav_fruit = 'banana' then 1
           else 0
         end) / sum(1)   -- why does division always yield 0? "+", "-", and "*" all behave as expected.
         * 100 as banana_pct,
     sum(1) as total
from 
    survey s
group by
    s.fav_color;

结果：

fav_color   banana banana_pct  total
------------------------------------
blue        0      0            1
green       0      0            1
purple      0      0            1
red         1      0            2
yellow      1      0            2

我期待的是：

fav_color   banana banana_pct  total
------------------------------------
blue        0      0           1
green       0      0           1
purple      0      0           1
red         1      50          2
yellow      1      50          2

请帮助我达到我的期望吗？