private function appendRelation(QueryBuilder $queryBuilder, $relation, $values, $operator, $alias)
    {
        switch ($operator) {
            case 'or':
                return $this->appendRelationOr($queryBuilder, $relation, $values, $alias);
            case 'and':
                return $this->appendRelationAnd($queryBuilder, $relation, $values, $alias);
        }

        return [];
    }