Class RawSQL

django/db/models/expressions.py:1268–1300

class RawSQL(Expression):
    allowed_default = True

    def __init__(self, sql, params, output_field=None):
        if output_field is None:
            output_field = fields.Field()
        self.sql, self.params = sql, params
        super().__init__(output_field=output_field)

    def __repr__(self):
        return "{}({}, {})".format(self.__class__.__name__, self.sql, self.params)

    def as_sql(self, compiler, connection):
        return "(%s)" % self.sql, self.params

    def get_group_by_cols(self):
        return [self]

    def resolve_expression(
        self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
    ):
        # Resolve parents fields used in raw SQL.
        if query.model:
            for parent in query.model._meta.all_parents:
                for parent_field in parent._meta.local_fields:
                    if parent_field.column.lower() in self.sql.lower():
                        query.resolve_ref(
                            parent_field.name, allow_joins, reuse, summarize
                        )
                        break
        return super().resolve_expression(
            query, allow_joins, reuse, summarize, for_save
        )


class Star(Expression):