sql - 如何在 PostgreSQL 中获取最多两位小数的百分比值？

Question

我编写了以下查询来获取单个用户的计数和百分比值:

select a.user_type,a.count,a.count * 100/(select sum(sessions) from user_type) as percentage
from
(select user_type, sum(sessions) as count 
from user_type 
group by user_type
order by user_type)  a,
(select user_type, sum(sessions) as count 
from user_type 
group by user_type
order by user_type)  b
where a.user_type = b.user_type and a.count = b.count
group by a.user_type,a.count

百分比值接近 7.35684648。有人可以告诉我应该做哪些更改才能根据我的要求获得 % 值。

Answer 1

您可以使用 round function .

select a.user_type,a.count,round(a.count * 100/(select sum(sessions) from user_type),2) ...

这应该将百分比值截断为小数点后两位。