Class Join

lib/sqlalchemy/sql/selectable.py:1270–1712

Represent a ``JOIN`` construct between two :class:`_expression.FromClause` elements. The public constructor function for :class:`_expression.Join` is the module-level :func:`_expression.join()` function, as well as the :meth:`_expression.FromClause.join` method of any :c

class Join(roles.DMLTableRole, FromClause[_KeyColCC_co]):
    """Represent a ``JOIN`` construct between two
    :class:`_expression.FromClause`
    elements.

    The public constructor function for :class:`_expression.Join`
    is the module-level
    :func:`_expression.join()` function, as well as the
    :meth:`_expression.FromClause.join` method
    of any :class:`_expression.FromClause` (e.g. such as
    :class:`_schema.Table`).

    .. seealso::

        :func:`_expression.join`

        :meth:`_expression.FromClause.join`

    """

    __visit_name__ = "join"

    _traverse_internals: _TraverseInternalsType = [
        ("left", InternalTraversal.dp_clauseelement),
        ("right", InternalTraversal.dp_clauseelement),
        ("onclause", InternalTraversal.dp_clauseelement),
        ("isouter", InternalTraversal.dp_boolean),
        ("full", InternalTraversal.dp_boolean),
    ]

    _is_join = True

    left: FromClause
    right: FromClause
    onclause: Optional[ColumnElement[bool]]
    isouter: bool
    full: bool

    def __init__(
        self,
        left: _FromClauseArgument,
        right: _FromClauseArgument,
        onclause: Optional[_OnClauseArgument] = None,
        isouter: bool = False,
        full: bool = False,
    ):
        """Construct a new :class:`_expression.Join`.

        The usual entrypoint here is the :func:`_expression.join`
        function or the :meth:`_expression.FromClause.join` method of any
        :class:`_expression.FromClause` object.

        """

        # when deannotate was removed here, callcounts went up for ORM
        # compilation of eager joins, since there were more comparisons of
        # annotated objects.   test_orm.py -> test_fetch_results
        # was therefore changed to show a more real-world use case, where the