总和（案例结果不正确答案

【问题标题】：Sum(case results not right总和（案例结果不正确
【发布时间】：2012-07-19 13:38:43
【问题描述】：

我有一个联系人表，其中包括每个联系人在附近居住的时间长度：

 ID    First_Name   Last_Name    Neighborhood_Time
 1      John         Smith        1-2 years
 2      Mary         Jones        2-5 years
 3      Dennis       White        2-5 years
 4      Martha       Olson        5+ years
 5      Jeff         Black        5+ years
 6      Jean         Rogers       2-5 years

我想显示时间百分比，结果如下：

 One_to_2_Years   Two_to_5_Years       5+_Years
      16                50                 33

这是我正在使用的：

 select 
 sum(case when Neighborhoods_time ='1-2 years' then 1 else 0 end)*100/(select count(*) from contact) as One_to_2_Years,    
 sum(case when Neighborhoods_time ='2-5 years' then 1 else 0 end)*100/(select count(*) from contact) as Two_to_6_Years,
 sum(case when Neighborhoods_time ='5+years' then 1 else 0 end)*100/(select count(*) from contact) as Six_to_10_Years
  from dbo.contact

这是我的结果：

  One_to_2_Years   Two_to_5_Years       5+_Years
        0               0                  16
        16              33                 0
        0               16                 16

我看到每列下的数字都是正确的，但我在对它们求和时遇到了问题。

我错过了什么？

谢谢。

【问题讨论】：

您不需要在每列中使用/(select count(*) from contact)，只需使用/ count(*) AS ，因为您已经从contact中选择了
谢谢 Nicola，你是对的。
@GarethD 感谢您的帮助。

标签： sql sum case

【解决方案1】：

按 Neighborhoods_time 添加组

【讨论】：

【解决方案2】：

你的查询的基础可以像

select 
    Neighborhood_Time,
    100*COUNT(*)/(Select COUNT(*) from contact) as percentvalue
from 
    contact
group by 
    Neighborhood_Time

如果你想水平排列，那么你应该使用枢轴

select
*
from
(
select 
    Neighborhood_Time,
    100*COUNT(*)/(Select COUNT(*) from contact) as percentvalue
from 
    contact
group by 
    Neighborhood_Time
) src
PIVOT
( SUM(percentvalue) for Neighborhood_Time in ([1-2 years],[2-5 years],[5+ years])) as pt

【讨论】：