使用休眠标准选择组中的最后一条记录

时间:2013-10-11 02:04:50

标签: hibernate

我想使用标准

获取此SQL
select A.evaluated_employee_id, A.created_date, A.total_grade
from employee_performance_assessment A
join
(  select evaluated_employee_id, max(created_date) as maxdate, status, total_grade
    from employee_performance_assessment
    group by evaluated_employee_id
) B on A.evaluated_employee_id = B.evaluated_employee_id and A.created_date = B.maxDate

我正在做以下

    DetachedCriteria dc = DetachedCriteria.forClass(EmployeePerformanceAssessmentBO.class);
    dc.createAlias("evaluatedEmployee", "e");
    dc.setProjection(Projections.projectionList().add(Projections.max("createdDate"))
.add(Projections.groupProperty("evaluatedEmployee")));
 dc.addOrder(Order.asc("e.lastName")).addOrder(Order.asc("createdDate"));                   
    dc.setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY);
    return getDAOHibernateTemplate().findByCriteria(dc);

但是这会在WHERE子句中生成子查询 知道如何从同一个表(类)中加入两个标准吗?

1 个答案:

答案 0 :(得分:4)

找到解决方案。基本上改变了原始查询:

select A.evaluated_employee_id, A.created_date, A.total_grade
from employee_performance_assessment A
where A.created_date = 
(  select max(created_date)
    from employee_performance_assessment
    where A.evaluated_employee_id = evaluated_employee_id 
    group by evaluated_employee_id
) 

因此,我不是加入子查询,而是在where子句中比较created_date。 休眠中的等价物是:

DetachedCriteria dc = DetachedCriteria.forClass(EmployeePerformanceAssessmentBO.class, "performanceAssessment");
dc.createAlias("evaluatedEmployee", "e");

dc.addOrder(Order.asc("e.lastName")).addOrder(Order.asc("createdDate"));

if (assessmentsSearch.isOnlyLastAssessment()){
   DetachedCriteria dc2 = DetachedCriteria.forClass(EmployeePerformanceAssessmentBO.class, "performanceAssessmentSubQuery");
   dc2.setProjection(Projections.projectionList().add(Projections.max("createdDate")));
   dc2.add(Expression.eqProperty("performanceAssessment.evaluatedEmployee.id", "performanceAssessmentSubQuery.evaluatedEmployee.id"));

   dc.add(Subqueries.propertyEq("createdDate", dc2));
}

希望它可以帮助别人。

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