I'm using Doctrine ORM with PHP and with MariaDB. I'm trying to fetch only the paid orders from the database. Here's my code:

    public function listOrders($filter = [], $limit = 50, $offset = 0): array {
        $qb = $this->entityManager->createQueryBuilder();

        $page = isset( $filter['page'] ) ? $filter['page'] - 1 : $offset;
        $perPage = $filter['perPage'] ?? $limit;
        $firstResult = $page * $perPage;
        $orderBy = isset($filter['sortBy'])
            ? 'orders.'.$filter['sortBy']
            : 'orders.created';

        $qb
            ->select('orders')
            ->from(OrderData::class, 'orders')
            ->setFirstResult($firstResult)
            ->setMaxResults($perPage)
            ->orderBy($orderBy, isset($filter['sortDesc']) ? 'ASC' : 'DESC ');
            
        // Filter by orders that are paid
        if (isset($filter['paid']) && $filter['paid']) {
            $qb
                ->leftJoin('orders.items', 'item')
                ->addSelect('SUM(item.price) AS item_prices')
                ->leftJoin('orders.transactions', 'transaction')
                ->addSelect('SUM(transaction.price) AS paid_amount')
                ->andWhere(
                    $qb->expr()->eq(
                        'paid_amount',
                        'item_prices'
                    ) // Get only paid orders
                );
        }

        ...
    }

The error I'm getting:

An exception occurred while executing

SELECT
  DISTINCT id_0
FROM
  (
    SELECT
      DISTINCT id_0,
      created_2
    FROM
      (
        SELECT
          o0_.id AS id_0,
          o0_.token AS token_1,
          o0_.created AS created_2,
          o0_.updated AS updated_3,
          o0_.requestId AS requestId_4,
          SUM(o1_.price) AS sclr_5,
          SUM(o2_.price) AS sclr_6,
          o1_.price AS price_7,
          o2_.price AS price_8,
          o1_.type AS type_9
        FROM
          orders o0_
          LEFT JOIN orders_items o1_ ON o0_.id = o1_.order_id
          LEFT JOIN orders_items_journeys o3_ ON o1_.id = o3_.id
          LEFT JOIN orders_items_railpasses o4_ ON o1_.id = o4_.id
          LEFT JOIN orders_items_articles o5_ ON o1_.id = o5_.id
          LEFT JOIN orders_items_distributions o6_ ON o1_.id = o6_.id
          LEFT JOIN orders_items_giftcard o7_ ON o1_.id = o7_.id
          LEFT JOIN orders_transactions o2_ ON o0_.id = o2_.order_id
        WHERE
          sclr_6 = sclr_5
        ORDER BY
          o2_.created DESC
      ) dctrn_result_inner
    ORDER BY
      created_2 DESC
  ) dctrn_result
LIMIT
  30

':SQLSTATE[42S22]: Column not found: 1054 Unknown column 'sclr_6' in 'where clause'

The syntax is valid, but it can not recognize the generated column for some reason.

Any help would be appreciated.