仅来自自定义查询的最后一条记录 [英] Only last record from Custom query
本文介绍了仅来自自定义查询的最后一条记录的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
以下查询返回一个列表,但我只对列表的最后一个元素感兴趣.
The following query return a list but I am only interested in the last element of the list.
@Query("SELECT r FROM Reservation r WHERE r.reservationSeance.id=:seanceId AND r.seanceDate=:seanceDate")
public Reservation findReservationBySeanceDateAndSeanceId(@Param("seanceId") int seanceId, @Param("seanceDate") java.time.LocalDate seanceDate);
我应该如何重写 SQL-Query 以实现我的想法?
How shall I rewrite the SQL-Query in order to implement my idea?
推荐答案
一种可能的解决方案是使用 ORDER BY r.id DESC
:
One possible solution is to use ORDER BY r.id DESC
:
@Query("SELECT r FROM Reservation r " +
"WHERE r.reservationSeance.id=:seanceId AND r.seanceDate=:seanceDate " +
"ORDER BY r.id DESC")
public Reservation findReservationBySeanceDateAndSeanceId(
@Param("seanceId") int seanceId,
@Param("seanceDate") java.time.LocalDate seanceDate, Pageable pageable);
并且因为在 JPQL 中没有办法使用限制,你可以使用 Pageable
and because there are no way to use limit in JPQL, you can use Pageable
Pageable pageable = new PageRequest(0, 1);
Reservation reservation = r.findReservationBySeanceDateAndSeanceId(seanceId, seanceDate, pageable);
<小时>
另一种没有查询的可能解决方案:
Another possible solution without Query :
public Reservation findTop1ByReservationSeanceAndSeanceDateOrderByIdDesc(
ReservationSeanceEntity reservationSenace,
java.time.LocalDate seanceDate
)
在第二个解决方案中,您必须传递 ReservationSeance
对象而不是 ReservationSeance
的 id
,查询可以读作:
In this second solution you have to pass the ReservationSeance
Object and not the id
of ReservationSeance
, the query can be read as :
Find top 1 (first one) by `ReservationSeance` and `SeanceDate` order by `Id` Desc order
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