java示例代码_在jpa/hibernate中实现这个简单的关联

java示例代码_在jpa/hibernate中实现这个简单的关联

@Entity
@Table(name="tableA")
Class A

   @ManyToOne
   @JoinColumn(name = "B_ID")
   B b;

   // some other properties



@Entity
@Table(name="tableB")
Class B

   @OneToMany(mappedBy = "b")
   List Set<A> listOfA= new ArrayList<A>();  

  // some other properties

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java示例代码_在JPA/Hibernate中使用聚合函数调用SQL查询

java示例代码_在JPA/Hibernate中使用聚合函数调用SQL查询

List<ViolationSummaryDTO> result = em.createQuery(
                "SELECT new ViolationSummaryDTO(v.counName, v.siteNumber," +
                    "sum(case when v.pvClStati.clstId = 1 then 1 else 0 end) as suspectedViolation," +
                    "sum(case when v.pvClStati.clstId = 2 then 1 else 0 end) as confirmedViolation," +
                    "sum(case when v.pvClStati.clstId = 3 then 1 else 0 end) as confirmedNoViolation," +
                    "sum(case when v.pvClStati.clstId = 0 then 1 else 0 end) as notDetermined," +
                    "COUNT(*) as total)" +
                " FROM Violation v" +
                " WHERE v.trial.id = " + trialId +
                " GROUP BY v.counName, v.siteNumber", ViolationSummaryDTO.class).getResultList();