springjpaspring-dataspring-data-jpajpql

Can I limit the result of JPQL to just return one result?


I would like to do something like this (in Spring Data JPA) in a repository interface:

interface myRepository extends JpaRepository<A, Long> {
    @Query("select a from A a where a.x = :x")
    A findFirstBySomeCondition(int x);
}

But I only need the first result. (Edited: The actual query condition is much complex so I would prefer to use @Query instead of findFirst or findTop...)

I don't want to use criteria api, because it's verbose.

I don't want to use the the native query cause I will have to compose the query string manually.

So, is there an solution left though, given the restricted requirement above?

Thanks!


Solution

  • The results of query methods can be limited via the keywords first or top, which can be used interchangeably. An optional numeric value can be appended to top/first to specify the maximum result size to be returned.

    interface myRepository extends JpaRepository<A, Long> {
        @Query("select a from A a where a.x = :x")
        Page<A> findFirstBySomeCondition(@Param("x") int x,Pageable pageable);
    }
    

    Impletation Class:

    Page<A> results = repository.findFirstBySomeCondition(x,new   PageRequest(0, 1));
    A object = results.getContent.get(0);