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出于某种原因，我无法判断，当我尝试使用子查询从 CriteriaQuery 获取列表时出现异常。有人请帮忙！！！这是代码：

public String[] getProductsDistinctBySubQueriesName(String category) {
    CriteriaBuilder builder = em.getCriteriaBuilder();
    CriteriaQuery<Tuple> criteria = builder.createTupleQuery();
    //subquery
    Subquery<Integer> subqueries = criteria.subquery(Integer.class);
    Root<Productscategory> productCategory = subqueries.from(Productscategory.class);
    subqueries.select(productCategory.<Integer>get("productscategoryid"))
            .where(builder.equal((productCategory.<String>get("productcatgoryname")), category));
    //outerquery
    Root<Products> root = criteria.from(Products.class);
    criteria.multiselect(root.get(Products_.productname)).distinct(true)
            .where(builder.in(root.get("productscategoryid")).value(subqueries));


    List<Tuple> tupleResult = em.createQuery(criteria).getResultList(); // the exception is thrown here
    String[] arrayProducts = new String[tupleResult.size()];
    for (int i = 0; i < tupleResult.size(); i++) {
        arrayProducts[i] = (String) tupleResult.get(i).get(0);
    }
    return arrayProducts;

}

这是例外

内部异常：com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以在 '.productscategoryid FROM productscategory t1 WHERE (t1.productcatgoryname = 'Pri' at line 1 错误代码：1064 错误代码：1064 调用：SELECT DISTINCT t0.productname FROM products t0 WHERE t0.productscategoryid IN (SELECT t1.productscategoryid.t1.productscategoryid FROM productscategory t1 WHERE (t1.productcatgoryname = ?)) bind => [1 parameter bound] Call: SELECT DISTINCT t0.productname FROM products t0 WHERE t0。 productscategoryid IN (SELECT t1.productscategoryid.t1.productscategoryid FROM productscategory t1 WHERE (t1.productcatgoryname = ?)) bind => [1 参数绑定] 查询：469) 在 com.inventory.service.ProductsServices.getProductsDistinctBySubQueriesName(ProductsServices.java:112) 在 com.inventory.service.ProductsServices.getAllByName(ProductsServices.java:211) 在 com.inventory.server.InventorySocketRequest.getServiceClass(InventorySocketRequest.java :77) at com.inventory.server.InventorySocketRequest.run(InventorySocketRequest.java:44) 原因：异常 [EclipseLink-4002] (Eclipse Persistence Services - 2.5.1.v20130918-f2b9fc5): org.eclipse.persistence.exceptions .DatabaseException 内部异常：com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以在 '.productscategoryid FROM productscategory t1 WHERE (t1.productcatgoryname = 'Pri' AbstractSession.executeQuery(AbstractSession.java:1775) 在 org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1740) 在 org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java: 258）... 5 更多原因：com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以获取正确的语法，以便在 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 的 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 的第 1 行的 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 附近的 '.productscategoryid FROM productscategory t1 WHERE (t1.productcatgoryname = 'Pri') 附近使用正确的语法。反射.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 在 sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:

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1 回答 1

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尝试使用此查询而不是您的查询，这与 EclipseLink 提供程序完美配合，不确定您的查询在 eclipselink 中不起作用但在 hibernate 中起作用，我测试了下面的查询，您将能够根据 ProductCategoryName 选择产品。

    EntityManagerFactory emf = Persistence.createEntityManagerFactory("jpaQuery");
    EntityManager em = emf.createEntityManager();

    String category = "cat2";

    CriteriaBuilder builder = em.getCriteriaBuilder();

    CriteriaQuery<Products> query = builder.createQuery(Products.class);
    Root<Products> products = query.from(Products.class);

    Subquery<Productscategory> squery = query.subquery(Productscategory.class);
    Root<Productscategory> productCategoryRoot = squery.from(Productscategory.class);
    Join<Productscategory, Products> join = productCategoryRoot.join("productsCollection");

    squery.select(productCategoryRoot)
    .where(builder.equal(join, products), builder.equal(productCategoryRoot.get("productcatgoryname"), category));

    query.where( builder.exists(squery));
    List<Products> productList = em.createQuery(query).getResultList(); 

    for (Products product : productList) {
           System.out.println(product);
    }

在哪个类别中是您要搜索的类别的名称..

这解决了问题 =).. 如果可行，请不要忘记接受答案 XD。

于 2014-01-26T21:43:05.300 回答