Java 使用QueryDsl从子查询创建别名

我的目标是转换这个

SQL查询

：

select a.*, (select count(DOGS.DOG_ID) from DOGS where a.DOG_ID = 
DOGS.DOG_ID) cnt
from ANIMALS a
order by cnt desc ;

我创建了一个

QueryDsl

查询，如下所示：

createQuery()
            .select(Projections.constructor(AnimalsDto.class, animal.animalId, animal.firstName,
                    Expressions.as(subQueryForDogsCount(dogs, animal), "cnt")))
            .from(animal).orderBy(new OrderSpecifier<>(Order.ASC, Expressions.asString("cnt"))).fetch();

[select 
animal.animalId, 
prospect.firstName,  
(select count(DOGS.dogId)
from DOGS dogs
where dogs.dogId = animal.dogId) as cnt
from ANIMAL animal
order by ?1 desc]

当我记录该查询时，我得到如下结果：

createQuery()
            .select(Projections.constructor(AnimalsDto.class, animal.animalId, animal.firstName,
                    Expressions.as(subQueryForDogsCount(dogs, animal), "cnt")))
            .from(animal).orderBy(new OrderSpecifier<>(Order.ASC, Expressions.asString("cnt"))).fetch();

[select 
animal.animalId, 
prospect.firstName,  
(select count(DOGS.dogId)
from DOGS dogs
where dogs.dogId = animal.dogId) as cnt
from ANIMAL animal
order by ?1 desc]

当我想要执行它时，我得到了一个

nullpointerexpection

，我认为问题可能出现在最后一个列表中：

？1

。为什么

querydsl

看不到此别名？也许还有其他方法可以为它创建别名吗