java - How to get float value in ResultSet of Hibernate Query?

Question

I have the following query

select sum(r.score)/count(r) from Rating as r
    group by r.item
    order by sum(r.score)/count(r) desc

My problem is that hibernate rounds the result sum(r.score)/count(r).

How can I force Hibernate to return the float value of the result?

Answer 1

如果您只想找到一个平均值，那么您可以使用avg()聚合函数，它总是返回一个Double.

select avg(r.score) from Rating as r
    group by r.item
    order by avg(r.score) desc

Answer 2

avg最适合这种情况。对于要转换为双精度的一般情况，您可以使用 CAST：

select sum(r.score) / (CAST (count(r) AS DOUBLE PRECISION)) from Rating as r
    group by r.item
    order by sum(r.score) / (CAST (count(r) AS DOUBLE PRECISION)) desc