public function loadChildBlocksData(Block $block, ?string $placeholder = null): array
    {
        $query = $this->getBlockSelectQuery();
        $query->where(
            $query->expr()->eq('b.parent_id', ':parent_id')
        )
        ->setParameter('parent_id', $block->id, Type::INTEGER)
        ->addOrderBy('b.placeholder', 'ASC')
        ->addOrderBy('b.position', 'ASC');

        if ($placeholder !== null) {
            $query->andWhere(
                $query->expr()->eq('b.placeholder', ':placeholder')
            )
            ->setParameter('placeholder', $placeholder, Type::STRING);
        }

        $this->applyStatusCondition($query, $block->status, 'b.status');

        return $query->execute()->fetchAll(PDO::FETCH_ASSOC);
    }