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我在我的数据库表Foo上有几条记录,我需要聚合一个列来合计它的值。JPA NamedQuery与聚合函数和组合使用
表示表的实体是这样的:
@Entity
@Table(name = "FOO")
@NamedQueries({
@NamedQuery(name = "Foo.total", query = "SELECT f.id, sum(f.someInt) AS
SOME_INT, f.parentId FROM Foo f where f.parentId = 'root' group by
p.parentId"),
@NamedQuery(name = "Foo.findAll", query = "SELECT f from Foo f") })
public class Foo {
@Id
@Column(name = "ID", insertable = false, updatable = false)
private String id;
@Column(name = "PARENT_ID", insertable = false, updatable = false)
private String parentId;
@Column(name = "SOME_INT", insertable = false, updatable = false)
private Integer someInt;
public Foo() {
}
}
如果我把这个在我的DAO服务豆:
entityManager.createNamedQuery("Foo.total", Foo.class).getResultList();
我得到这个错误:
Caused by: java.lang.IllegalArgumentException: Cannot create TypedQuery for query with more than one return using requested result type [Foo]
看来是临时t JPA无法将返回值与对象Foo相匹配。如果是这样,我该如何使这个工作?
如果我调用其他@NamedQuery“Foo.findAll”,它工作正常。
它工作。非常感谢你 – TiagoH