def get_count(self, using):
        """
        Performs a COUNT() query using the current filter constraints.
        """
        obj = self.clone()
        if len(self.select) > 1 or self.aggregate_select or (self.distinct and self.distinct_fields):
            # If a select clause exists, then the query has already started to
            # specify the columns that are to be returned.
            # In this case, we need to use a subquery to evaluate the count.
            from django.db.models.sql.subqueries import AggregateQuery
            subquery = obj
            subquery.clear_ordering(True)
            subquery.clear_limits()

            obj = AggregateQuery(obj.model)
            try:
                obj.add_subquery(subquery, using=using)
            except EmptyResultSet:
                # add_subquery evaluates the query, if it's an EmptyResultSet
                # then there are can be no results, and therefore there the
                # count is obviously 0
                return 0

        obj.add_count_column()
        number = obj.get_aggregation(using=using)[None]

        # Apply offset and limit constraints manually, since using LIMIT/OFFSET
        # in SQL (in variants that provide them) doesn't change the COUNT
        # output.
        number = max(0, number - self.low_mark)
        if self.high_mark is not None:
            number = min(number, self.low_mark - self.high_mark)

        return number
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/db/models/sql/query.py/Query.get_count/swapped operands of `-`