Question

如何为下面的SQL编写JPA查询？

select * from opstatus o where o.OPERATIONTYPE=2 and o.RECEIVEDFLAG =2 and o.SENDTIME in (select max(o1.SENDTIME)from opstatus o1 where (o1.OPERATIONTYPE=2 and o1.RECEIVEDFLAG =2) group by o1.dn);

尝试运行以下查询

result = em.createQuery("select o from DTO o where "
+ "o.operationType=:operationType"
+ " and o.receivedFlag = :receivedFlag"
+ " and o.startTime in (select max(o1.startTime)from DTO o1 where   
o1.receivedFlag = :receivedFlag group by o1.Dn) order by o.startTime").
setParameter("operationType","2").
setParameter("receivedFlag", "2").getResultList();

然而，在运行时，下面的查询得到了生成，其中包含额外的'group by T2.DN'，我们得到'org.apache.openjpa.persistence.PersistenceException：ORA-00979：不是GROUP BY表达式'

SELECT t0.OPERATIONID，t0.CURRENTSTEP，t0.DETAILEDSTEPS，t0.DN，t0.OPERATIONTYPE，t0.RECEIVEDFLAG，t0.REQUESTID，t0.SENDTIME from OPSTATUS t0，OPSTATUS t2 WHERE（t0.OPERATIONTYPE =？AND t0 .RECEIVEDFLAG =？AND t0.SENDTIME IN（选择MAX（t1.SENDTIME）来自OPSTATUS t1 WHERE（t1.OPERATIONTYPE =？AND t1.RECEIVEDFLAG =？）GROUP BY t1.DN））GROUP BY t2.DN [params =？，？，？，？]

如何防止额外的'分组'被追加？我尝试添加'order by o.sendtime'没用。

Answer 1

您的意思是选择每个Dn组中的最后一个条目。如果两个不同的Dn具有相同的startTime，并且只有一个是最后一个（最大），则查询将失败。由于子查询中的o1未链接到外部o，OpenJPA将生成FROM OPSTATUS t0, OPSTATUS t2

也许您可以更改查询。

"select o from DTO o where "
+ "o.operationType=:operationType"
+ " and o.receivedFlag = :receivedFlag"
+ " and not exists (select o1 from DTO o1 where   
o1.receivedFlag = :receivedFlag and o1.Dn = o.Dn and o1.startTime > o.startTime) order by o.startTime"

JPA查询附加组

1 个答案: