raw_join.py

class RawJoin(Join):
    u"""Позволяет внедрить в QuerySet произвольный JOIN.

    banners_qs = Banner.objects.extra(where=['my_join_table.status = 123'])

    Join('LEFT JOIN (XXX) b1 ON b1.id = abcd ', ()).inject(banners_qs)
    """

    def __init__(self, raw_sql, params):
        # Используемые опции.
        self.raw_sql = raw_sql
        self.params = params

        # Соответствие интерфейса.
        self.table_alias = 'raw_join'
        self.table_name = None
        self.parent_alias = None
        self.join_field = None
        self.join_cols = None
        self.join_type = None
        self.nullable = None

    def as_sql(self, compiler, connection):
        return self.raw_sql, self.params

    def inject(self, queryset):
        queryset.query.get_initial_alias()
        queryset.query.table_alias(self.table_alias, True)
        queryset.query.alias_map[self.table_alias] = self