java - JPQL 运算符返回 java.lang.IllegalStateException - 节点 : org. hibernate.hql.internal.ast.tree.MethodNode 没有数据类型

Question

我一直在 Stackoverflow 上工作，并测试了一些建议，但没有成功。

我有这个 SELECT OPERATOR('ToChar', a.created,'MM-YYYY') AS _month, COUNT(a) FROM Account AS a GROUP BY _month 查询，该查询返回以下错误，令我失望的是，我一直没能解决。

错误是:

java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.MethodNode 
 \-[METHOD_CALL] MethodNode: '('
    +-[METHOD_NAME] IdentNode: 'OPERATOR' {originalText=OPERATOR}
    \-[EXPR_LIST] SqlNode: 'exprList'
       +-[QUOTED_STRING] LiteralNode: ''ToChar''
       +-[DOT] DotNode: 'account0_.created' {propertyName=created,dereferenceType=PRIMITIVE,getPropertyPath=created,path=a.created,tableAlias=account0_,className=com.eoh.permasys.entities.Account,classAlias=a}
       |  +-[ALIAS_REF] IdentNode: 'account0_.id' {alias=a, className=com.eoh.permasys.entities.Account, tableAlias=account0_}
       |  \-[IDENT] IdentNode: 'created' {originalText=created}
       \-[QUOTED_STRING] LiteralNode: ''MM-YYYY''

如果有人能帮助我，我将不胜感激。谢谢。

Answer 1

以防其他人遇到类似的问题。我最终使用不同的 JPQL 查询来实现我的目标。

SELECT EXTRACT(MONTH FROM a.created), EXTRACT(YEAR FROM a.created), COUNT(a) FROM Account AS a GROUP BY EXTRACT(MONTH FROM a.created), EXTRACT(YEAR FROM a.created)

然后我返回 List<Object[]> 。

完整的方法是

public List<Object[]> countAccountsCreatedPerMonth() {
        EntityManager em = getEntityManager();
        try {
            Query q = em.createQuery("SELECT EXTRACT(MONTH FROM a.created), EXTRACT(YEAR FROM a.created), COUNT(a) FROM Account AS a GROUP BY EXTRACT(MONTH FROM a.created), EXTRACT(YEAR FROM a.created)");
            return q.getResultList();
        } finally {
            em.close();
        }
    }

我不知道这是否是最好的方法，但这肯定对我有用。