使用TIMESTAMPDIFF和JPA标准查询，并使用hibernate作为提供者

我有一个列设置和释放数据表，其中都包含时间戳。 我的目标是使用CriteriaQuery创建一个等效的SQL查询。

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

CriteriaBuilder＃diff（）函数显然不起作用，因为它需要数字参数，所以我尝试使用CriteriaBuilder＃函数：

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，当我试着运行这段代码时，它抛出了一个异常; 看起来文字不是呈现为常数，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}
       |  +-[ALIAS_REF] IdentNode: 'cdr0_.id' {alias=generatedAlias0, className=com.vtsl.domain.CDR, tableAlias=cdr0_}
       |  -[IDENT] IdentNode: 'setup' {originalText=setup}
       -[DOT] DotNode: 'cdr0_.release' {propertyName=release,dereferenceType=ALL,propertyPath=release,path=generatedAlias0.release,tableAlias=cdr0_,className=com.vtsl.domain.CDR,classAlias=generatedAlias0}
          +-[ALIAS_REF] IdentNode: 'cdr0_.id' {alias=generatedAlias0, className=com.vtsl.domain.CDR, tableAlias=cdr0_}
          -[IDENT] IdentNode: 'release' {originalText=release}

所以我尝试匿名覆盖LiteralExpression＃render直接返回我提供给方法的字符串，但是这个例外。

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'
       +-[IDENT] IdentNode: 'SECOND' {originalText=SECOND}
       +-[DOT] DotNode: 'cdr0_.setup' {propertyName=setup,dereferenceType=ALL,propertyPath=setup,path=generatedAlias0.setup,tableAlias=cdr0_,className=com.vtsl.domain.CDR,classAlias=generatedAlias0}
       |  +-[ALIAS_REF] IdentNode: 'cdr0_.id' {alias=generatedAlias0, className=com.vtsl.domain.CDR, tableAlias=cdr0_}
       |  -[IDENT] IdentNode: 'setup' {originalText=setup}
       -[DOT] DotNode: 'cdr0_.release' {propertyName=release,dereferenceType=ALL,propertyPath=release,path=generatedAlias0.release,tableAlias=cdr0_,className=com.vtsl.domain.CDR,classAlias=generatedAlias0}
          +-[ALIAS_REF] IdentNode: 'cdr0_.id' {alias=generatedAlias0, className=com.vtsl.domain.CDR, tableAlias=cdr0_}
          -[IDENT] IdentNode: 'release' {originalText=release}

所以问题是：我该如何解决我想要做的这个操作，或者实现最初的目标？

我使用Hibernate，我的数据库是MySQL。

---

我遇到了同样的问题： SECOND将被撇号包围，查询将抛出异常。

我通过以下代码解决了这个问题：

CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<MyEntity> cq = builder.createQuery( MyEntity.class );
Root<MyEntity> root = cq.from( MyEntity.class );

javax.persistence.criteria.Expression<java.sql.Time> timeDiff = builder.function(
            "TIMEDIFF",
            java.sql.Time.class,
            root.<Date>get( "endDate" ),
            root.<Date>get( "startDate" ) );
javax.persistence.criteria.Expression<Integer> timeToSec = builder.function(
            "TIME_TO_SEC",
            Integer.class,
            timeDiff );

//lessThanOrEqualTo 60 minutes
cq.where( builder.lessThanOrEqualTo( timeToSec, 3600 ) );

return em.createQuery( cq ).getResultList();

这给了我相同的结果。

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