Method _can_join

lib/sqlalchemy/sql/selectable.py:1502–1523

(
        cls,
        left: FromClause,
        right: FromClause,
        *,
        consider_as_foreign_keys: Optional[
            AbstractSet[ColumnClause[Any]]
        ] = None,
    )

    @classmethod
    def _can_join(
        cls,
        left: FromClause,
        right: FromClause,
        *,
        consider_as_foreign_keys: Optional[
            AbstractSet[ColumnClause[Any]]
        ] = None,
    ) -> bool:
        if isinstance(left, Join):
            left_right = left.right
        else:
            left_right = None

        constraints = cls._joincond_scan_left_right(
            a=left,
            b=right,
            a_subset=left_right,
            consider_as_foreign_keys=consider_as_foreign_keys,
        )

        return bool(constraints)

    @classmethod
    @util.preload_module("sqlalchemy.sql.util")