SQL-如何对重复计数结果求和

问题描述

我的查询存在一些问题。

我想对员工的位置进行分类并根据地区进行计数，这是我的查询：

SELECT
    (CASE 
        WHEN location = 'India' THEN 'Asia' 
        WHEN location  = 'Italy' THEN 'Europe' 
        WHEN location  = 'Singapore' THEN 'Asia' 
        WHEN location  = 'Australia' THEN 'Australia' 
        ELSE NULL 
     END) AS Region,COUNT(location) AS Total_person 
FROM
    Location_tbl 
GROUP BY
    location

结果如下：

1. 亚洲= 1
2. 欧洲= 1
3. 亚洲= 1
4. 澳大利亚= 1

我想要的结果是这样的：

1. 亚洲= 2
2. 欧洲= 1
3. 澳大利亚= 1

你们能帮我解决问题的方法，以便我得到想要的结果。

解决方法

您需要在group by-

中添加自定义组

select 
CASE WHEN location in( 'India','Singapore') THEN 'Asia' WHEN location  = 'Italy' THEN 'Europe' WHEN location  = 'Australia' THEN 'Australia' END as Region,count(location) as Total_person from Location_tbl 
group by CASE WHEN location in( 'India','Singapore') THEN 'Asia' WHEN location  = 'Italy' THEN 'Europe' WHEN location  = 'Australia' THEN 'Australia' END

,

select 
    Region,count(Region) 
from 
    (select (CASE WHEN location = 'India' THEN 'Asia' WHEN location  = 'Italy' THEN 'Europe' WHEN location  = 'Singapore' THEN 'Asia' WHEN location  = 'Australia' THEN 'Australia' ELSE null END) as Region 
     from Location_tbl) tab 
group by 
    tab.Region

,

SELECT 
    location,CASE
        WHEN location = 'India' or 'Singapore' THEN 'Asia' 
        WHEN location = 'Italy' THEN 'Europe'
        WHEN location = 'Australia' THEN 'Australia'
        ELSE NULL
    END AS Region
FROM 
    Location_tbl
GROUP BY 
    location
ORDER BY 
    SUM(location);