相关疑难解决方法(0)

我有一个包含列设置和释放的数据表,两者都有时间戳.我的目标是使用CriteriaQuery在下面创建一个等价的SQL查询.

SQL查询:SELECT TIMESTAMPDIFF(SECOND, setup, released)) as sum_duration FROM calls

该CriteriaBuilder#DIFF()函数显然不工作,因为它需要有数字的参数,所以我尝试使用CriteriaBuilder#功能:

EntityManager entityManager = emProvider.get();

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();

CriteriaQuery<Integer> query = criteriaBuilder.createQuery();

Root<Thingy> thingyRoot = query.from(Thingy.class);

Path<DateTime> setup = root.get("setup");
Path<DateTime> release = root.get("release");

Expression secondLiteral = criteriaBuilder.literal("SECOND");

Expression func = criteriaBuilder.function("TIMESTAMPDIFF", Integer.class, secondLiteral, setup, release);

entityManager.createQuery(query).getResultList();

但是,当我尝试运行此代码时,它抛出异常; 似乎文字不是作为常量呈现,而是作为参数呈现:

java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.MethodNode 
 \-[METHOD_CALL] MethodNode: '('
    +-[METHOD_NAME] IdentNode: 'TIMESTAMPDIFF' {originalText=TIMESTAMPDIFF}
    \-[EXPR_LIST] SqlNode: 'exprList'
       +-[NAMED_PARAM] ParameterNode: '?' {name=param0, expectedType=null}
       +-[DOT] DotNode: 'cdr0_.setup' {propertyName=setup,dereferenceType=ALL,propertyPath=setup,path=generatedAlias0.setup,tableAlias=cdr0_,className=com.vtsl.domain.CDR,classAlias=generatedAlias0} …