code: private function getExpiredDueQueryBuilder($prefix)
      {
          $qb = $this->createQueryBuilder();
          $as = $this->getAlias();
          $ex = $qb->expr();
  
          return $qb
              ->andWhere($ex->gt($as . '.' . $prefix . 'Total', 0))
              ->andWhere($ex->isNull($as . '.' . $prefix . 'Date'))
              ->andWhere($ex->andX(
                  $ex->isNotNull($as . '.' . $prefix . 'DueDate'),
                  $ex->lt($as . '.' . $prefix . 'DueDate', ':today')
              ))
              ->setParameter('today', (new \DateTime())->setTime(0, 0, 0), Type::DATETIME);
      }
docs: Returns the expired due total.
  
  @param string $prefix
  
  @return \Doctrine\ORM\QueryBuilder