我真的需要在原生 @Query 中使用 countQuery 来进行分页吗？

Question

根据参考，本机查询分页需要

countQuery

（至少有一个示例）。但根据我的测试（Spring Boot 2.4.5），对于此类查询，@Query 分页无需

countQuery

即可工作：

public interface ARepository extends JpaRepository<A, Long>{
  @Query(value = "select * from a", nativeQuery = true)
  Page<A> findAllANative(Pageable pageable);

  @Query(value = "select count(a.id) as aCount, category.name as 
        categoryName " +
        "from a " +
        "join category on a.category_id=category.id " +
        "group by category.name",
        nativeQuery = true)
  List<CountView> findACountByCategoryNative(Pageable pageable);
}

如您所见，没有

countQuery

并且它们可以工作。

分页仅适用于这些特定查询，还是我可以在所有情况下省略

countQuery

？

Answer 1

countQuery 是可选的，如下所述

https://docs.spring.io/spring-data/jpa/docs/current/api/org/springframework/data/jpa/repository/Query.html#countQuery():~:text=Defines%20a% 20special%20count%20query%20that%20shall%20be%20used%20for%20pagination%20queries%20to%20lookup%20the%20total%20number%20of%20elements%20for%20a%20page.%20If%20none%20is%20configured%20we %20will%20derive%20the%20count%20query%20from%20the%20or%20countProjection%20query%20or%20countProjection()%20query%20if%20any