尝试从SQL构造JPA查询的问题

Question

我有一个在SQL中可以正常运行的查询，但我似乎无法在JPA中创建等效查询。 CriteriaBuilder“或”似乎没有执行“或”。

这些是表格...

Table A

id : Long : primary key
b_id : Long : foreign key to id of Table B
c_id : Long : foreign key to id of Table C

Table B

id: Long : primary key
loc_id: Long 

Table C

id: Long : primary key
d_id : Long : foreign key to id of Table D

Table D

id: Long : primary key
loc_id: Long 

这是表中的数据（按列出的字段的顺序... ...

Table A:
1,  1,  null
2,  2,  null
3,  null,   1

Table B:
1,  5
2,  6

Table C:
1,  1

Table D:
1,  5

并且我的sql查询通过外键在表B或表D中找到表A中loc_id为5的所有记录。 （2个结果-行ID 1和行ID 3）

select * from A 
LEFT JOIN B on B.id = a.b_id
LEFT JOIN C on C.id = a.c_id
LEFT JOIN D on D.id = c.d_id
WHERE B.loc_id = 5 or D.loc_id = 5

然而，我在JPA中努力编写相同的结果。我在下面尝试过创建2个谓词，当分别执行这些谓词时都会找到1条记录，但是当我“或”它们时，它们会产生0条记录。怎么会这样呢？

EntityManager em = getEntityManager();
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery cq = cb.createQuery();
Root<A> rt = cq.from(A.class);
List<Predicate> predicates = new ArrayList<>();

Join<B, A> join1 = rt.join("b_id", JoinType.INNER);
Join<C, A> join2 = rt.join("c_id", JoinType.INNER);
Join<D, C> join3 = join2.join("d_id", JoinType.INNER);
predicates.add(cb.or(cb.equal(join1.get("loc_id"), 5), cb.equal(join3.get("loc_id"), 5)));

CriteriaQuery x = cq.select(rt).where(predicates.toArray(new Predicate[predicates.size()]));
Query q = em.createQuery(x);
List<A> = q.getResultList();

感谢所有建议，谢谢....

Answer 1

这里是解决方法

EntityManager em = getEntityManager();
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<A> cq = cb.createQuery(A.class);
Root<A> rt = cq.from(A.class);

Join<B, A> joinB = rt.join("b_id", JoinType.LEFT);
Join<C, A> joinC = rt.join("c_id", JoinType.LEFT);
Join<D, C> joinD = joinC.join("d_id", JoinType.LEFT);

Predicate bPredicate = cb.equal(joinB.get("loc_id"), 5);
Predicate dPredicate = cb.equal(joinD.get("loc_id"), 5);

Predicate predicate = cb.or(bPredicate, dPredicate);

CriteriaQuery<A> x = cq.select(rt).where(predicate);
TypedQuery<A> q = em.createQuery(x);

List<A> result = q.getResultList();