2 结果百分比与同一张表

Question

select AGE,
(count (case when age > 22 then name end)*100.0/count(name)) as percentage
from student;

结果 20 30.0

select name, age,
(select 100*age/sum(age) over () as percentage from student) as percentage ,
(count(case when age > 22 then name end )*100.0/ count (name)) as Total_Perecentage 
from student
WHERE age > 22
GROUP BY 1,2;

结果

Elis    27  9   100.0
Mice    23  9   100.0
Sara    25  9   100.0

我的问题如何将 Total_percentage 从 100% 更新为 30%（所有结果都在一个表中）作为第一个查询

简单来说，30%是10个学生中超过22个的3个名字的总百分比。

Result

Answer 1

使用有条件地在表上聚合的子查询更容易：

SELECT name, age, 
       (SELECT 100 * AVG(age > 22) FROM student) AS Total_Perecentage 
FROM student 
WHERE age > 22

请参阅demo。
结果：

name	age	Total_Perecentage
Sara	25	30
Mice	23	30
Elis	27	30