getBackendListQuery example

        /** @var array $filter */
        $filter = $this->Request()->getParam('filter', []);
        $node = (int) $this->Request()->getParam('node');
        $preselectedNodes = $this->Request()->getParam('preselected');

        if (empty($filter)) {
            $node = !empty($node) ? $node : 1;
            $filter[] = ['property' => 'c.parentId', 'value' => $node];
        }

        $query = $this->getRepository()->getBackendListQuery(
            $filter,
            $this->Request()->getParam('sort', []),
            $this->Request()->getParam('limit'),
            $this->Request()->getParam('start')
        )->getQuery();

        $count = $this->em->getQueryCount($query);

        $data = $query->getArrayResult();

        foreach ($data as $key => $category) {
            

/** @var array $filter */
            $filter = $this->Request()->getParam('filter', []);

            $query = $this->getCategoryRepository()->getBlogCategoriesByParentQuery($categoryId);
            $blogCategories = $query->getArrayResult();

            $blogCategoryIds = $this->getBlogCategoryListIds($blogCategories);
            $blogCategoryIds[] = $categoryId;

            $repository = $this->getRepository();
            $dataQuery = $repository->getBackendListQuery($blogCategoryIds, $filter, $order, $offset, $limit);

            $totalCount = $this->getManager()->getQueryCount($dataQuery);
            $data = $dataQuery->getArrayResult();

            $this->View()->assign(['success' => true, 'data' => $data, 'totalCount' => $totalCount]);
        } catch (Exception $e) {
            $this->View()->assign(['success' => false, 'errorMsg' => $e->getMessage()]);
        }
    }

    /** * Reads all known blog categories to show it in the category treepanel */