Java JPA2条件查询,用于选择表A中未在表B中找到引用的记录
我有以下结构的表格Java JPA2条件查询,用于选择表A中未在表B中找到引用的记录,java,spring,postgresql,jpa-2.0,Java,Spring,Postgresql,Jpa 2.0,我有以下结构的表格 Table A { id <-- Primary key someColumn } Table B { id <-- Primary key someColumn idOfA <-- Foreign key mapping to Table A } 到目前为止,我所做的是 public List<A> getANotInB() { CriteriaBuilder criteriaBuilde
Table A {
id <-- Primary key
someColumn
}
Table B {
id <-- Primary key
someColumn
idOfA <-- Foreign key mapping to Table A
}
到目前为止,我所做的是
public List<A> getANotInB() {
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
// Select From Table B
CriteriaQuery<B> criteriaQueryB = criteriaBuilder
.createQuery(B.class);
Root<B> rootB = criteriaQueryB.from(B.class);
criteriaQueryB.select(rootB);
// Select records from Table A
CriteriaQuery<A> criteriaQueryA = criteriaBuilder.createQuery(A.class);
Root<A> rootA = criteriaQueryA.from(A.class);
criteriaQueryA.select(A);
// Create predicate
Predicate predicate = rootAttemptA.in(criteriaQueryB.getSelection());
criteriaQueryA.where(criteriaBuilder.not(predicate));
// Create query
TypedQuery<A> query = entityManager.createQuery(criteriaQueryA);
List<A> as= query.getResultList();
System.out.println(as);
return as;
}
public List getANotInB(){
CriteriaBuilder CriteriaBuilder=entityManager.getCriteriaBuilder();
//从表B中选择
CriteriaQuery criteriaQueryB=criteriaBuilder
.createQuery(B.class);
根rootB=标准查询B.from(B.class);
criteriaQueryB.select(rootB);
//从表A中选择记录
CriteriaQuery criteriaQueryA=criteriaBuilder.createQuery(A.class);
根rootA=criteriaQueryA.from(A.class);
选择(A);
//创建谓词
谓词谓词=rootAttemptA.in(criteriaQueryB.getSelection());
其中(criteriaBuilder.not(谓词));
//创建查询
TypedQuery query=entityManager.createQuery(criteriaQueryA);
List as=query.getResultList();
系统输出打印项次(as);
返回为;
}
我知道上面的代码是不正确的,我有很多基础知识。
好心帮忙
注意:我想使用JPA2标准查询
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
// Select distinct aid from B
CriteriaQuery<B> bQuery = cb.createQuery(B.class);
Root<B> bRoot = bQuery.from(B.class);
bQuery.select(bRoot.get("a").get("id")).distinct(true);
// Select * from A where aid not in ()
CriteriaQuery<A> aQuery = cb.createQuery(A.class);
Root<A> aRoot = aQuery.from(A.class);
aQuery.select(aRoot).where(cb.not(aRoot.get("id").in(bQuery)));
TypedQuery<A> query = entityManager.createQuery(aQuery);
List<A> result = query.getResultList();
CriteriaBuilder cb=entityManager.getCriteriaBuilder();
//从B中选择不同的援助
CriteriaQuery bQuery=cb.createQuery(B.class);
根bRoot=bQuery.from(B.class);
bQuery.select(bRoot.get(“a”).get(“id”)).distinct(true);
//从不在()中的where aid中选择*
CriteriaQuery我可以使用subquery()完成它,如下所示。发布它以便帮助他人
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
// select a from A a
CriteriaQuery<A> queryA = criteriaBuilder.createQuery(A.class);
Root<A> rootA = queryA.from(A.class);
queryA.select(rootA);
// Select distinct aId from B
CriteriaQuery<B> subQueryB = queryA.subquery(B.class);
Root<B> rootB = subQueryB.from(B.class);
bQuery.select(rootB.get("a")).distinct(true);
queryA.where(criteriaBuilder.not(criteriaBuilder.in(rootA.get("id").value(subQueryB))));
TypedQuery<A> query = entityManager.createQuery(aQuery);
List<A> result = query.getResultList();
CriteriaBuilder-CriteriaBuilder=entityManager.getCriteriaBuilder();
//从中选择一个
CriteriaQuery queryA=criteriaBuilder.createQuery(A.class);
根rootA=queryA.from(A.class);
queryA.select(rootA);
//从B中选择不同的援助
CriteriaQuery subQueryB=queryA.subquery(B.class);
根rootB=子查询B.from(B.class);
bQuery.select(rootB.get(“a”)).distinct(true);
where(criteriaBuilder.not(criteriaBuilder.in(rootA.get(“id”).value(subQueryB)));
TypedQuery=entityManager.createQuery(aQuery);
List result=query.getResultList();
谢谢@Mạnh为了显示方式显示您的A和B类,在您可以加入JPA CriteriaAdded Entity classesI之前,应该配置映射,但CriteriaQuery subQueryB=queryA.subquery(B.class);在我看来是不对的。它必须在子查询上赋值
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
// Select distinct aid from B
CriteriaQuery<B> bQuery = cb.createQuery(B.class);
Root<B> bRoot = bQuery.from(B.class);
bQuery.select(bRoot.get("a").get("id")).distinct(true);
// Select * from A where aid not in ()
CriteriaQuery<A> aQuery = cb.createQuery(A.class);
Root<A> aRoot = aQuery.from(A.class);
aQuery.select(aRoot).where(cb.not(aRoot.get("id").in(bQuery)));
TypedQuery<A> query = entityManager.createQuery(aQuery);
List<A> result = query.getResultList();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
// select a from A a
CriteriaQuery<A> queryA = criteriaBuilder.createQuery(A.class);
Root<A> rootA = queryA.from(A.class);
queryA.select(rootA);
// Select distinct aId from B
CriteriaQuery<B> subQueryB = queryA.subquery(B.class);
Root<B> rootB = subQueryB.from(B.class);
bQuery.select(rootB.get("a")).distinct(true);
queryA.where(criteriaBuilder.not(criteriaBuilder.in(rootA.get("id").value(subQueryB))));
TypedQuery<A> query = entityManager.createQuery(aQuery);
List<A> result = query.getResultList();