.. change::
    :tags: bug, sql
    :tickets: 4621

    The :class:`.Join` construct no longer considers the "onclause" as a source
    of additional FROM objects to be omitted from the FROM list of an enclosing
    :class:`.Select` object as standalone FROM objects. This applies to an ON
    clause that includes a reference to another  FROM object outside the JOIN;
    while this is usually not correct from a SQL perspective, it's also
    incorrect for it to be omitted, and the behavioral change makes the
    :class:`.Select` / :class:`.Join` behave a bit more intuitively.

