使用 JpaRepository Spring-data-jpa 对子列表总计数进行排序

Question

我有对实体进行分页和排序的需求。

@Entity
@Table(name = "CATEGORY", catalog = "")
public class CategoryEntity {
 private CategoryEntity categoryByParentCategoryId;
 private Set<CategoryEntity> categoriesByCategoryId;


@ManyToOne(fetch = FetchType.LAZY,optional = false, cascade = CascadeType.PERSIST)
@JoinColumn(name = "PARENT_CATEGORY_ID", referencedColumnName = "CATEGORY_ID")
public CategoryEntity getCategoryByParentCategoryId() {
    return categoryByParentCategoryId;
}

public void setCategoryByParentCategoryId(CategoryEntity categoryByParentCategoryId) {
    this.categoryByParentCategoryId = categoryByParentCategoryId;
}

@OneToMany(mappedBy = "categoryByParentCategoryId", cascade = CascadeType.PERSIST)
public Set<CategoryEntity> getCategoriesByCategoryId() {
    return categoriesByCategoryId;
}

public void setCategoriesByCategoryId(Set<CategoryEntity> categoriesByCategoryId) {
    this.categoriesByCategoryId = categoriesByCategoryId;
}

从 this link 和其他堆栈溢出答案中，我发现我可以使用 Paging Request like

进行排序和分页

Pageable size = new PageRequest(page, paginationDTO.getSize(),Sort.Direction.ASC, "id");

我的问题是我有一个 self join 父子关系，如上图所示，我需要根据子项的数量对父项进行排序，如下所示。

这里的Number of SubCategories是categoriesByCategoryId的大小。我需要在 PageRequest 中传递什么来代替 id 以根据子列表的大小进行排序。

PS。该模型有更多字段，但为了简短的问题，我只发布了相关字段

Answer 1

通过 this answer 我能够通过使用自定义查询实现要求，JPARepository 中的方法看起来像

@Query(
        value = "select c from CategoryEntity c " +
                " WHERE LOWER(c.categoryNameEn) LIKE LOWER(CONCAT('%',?2, '%')) AND activeInd = ?1 " +
                "AND c.categoryByParentCategoryId is null" +
                " Order By c.categoriesByCategoryId.size desc",
        countQuery = "select count(c) from CategoryEntity c " +
                " WHERE LOWER(c.categoryNameEn) LIKE LOWER(CONCAT('%',?2, '%')) AND activeInd = ?1" +
                " AND c.categoryByParentCategoryId is null"
)
Page<CategoryEntity> findAllActiveCategoriesByCategoriesByCategoryIdCountDesc(String activeInd, String categoryNameEn, Pageable pageable);

分页详细信息需要计数查询。

使用 JpaRepository Spring-data-jpa 对子列表总计数进行排序

Sort On Child List total count using JpaRepository Spring-data-jpa

java

sorting

repository

spring-data-jpa

spring-boot