Java 案例..在hql中查询时

我必须对照条目检查

null

。
我有一个address in person对象，所以我尝试按如下方式获取它

select new map(person.id as id,
               case when person.address is not empty 
               then person.address.city end as city) 
from Person person where person.id=:id

case..when

使用

where

子句吗

但是没有错误和结果。

试试这个：

select new map(person.id as id,coalesce(person.address,person.address.city )as city) from Person person

可能重复的