protected function makeQueryWhenNull(Builder $query, stdClass $rule, array $sqlOperator, $condition)
    {
        if ($sqlOperator['operator'] == 'NULL') {
            return $query->whereNull($rule->field, $condition);
        } elseif ($sqlOperator['operator'] == 'NOT NULL') {
            return $query->whereNotNull($rule->field, $condition);
        }

        throw new QBParseException('makeQueryWhenNull was called on an SQL operator that is not null');
    }