Class _label_reference

lib/sqlalchemy/sql/elements.py:3843–3870

Wrap a column expression as it appears in a 'reference' context. This expression is any that includes an _order_by_label_element, which is a Label, or a DESC / ASC construct wrapping a Label. The production of _label_reference() should occur when an expression is added to this cont

class _label_reference(ColumnElement[_T]):
    """Wrap a column expression as it appears in a 'reference' context.

    This expression is any that includes an _order_by_label_element,
    which is a Label, or a DESC / ASC construct wrapping a Label.

    The production of _label_reference() should occur when an expression
    is added to this context; this includes the ORDER BY or GROUP BY of a
    SELECT statement, as well as a few other places, such as the ORDER BY
    within an OVER clause.

    """

    __visit_name__ = "label_reference"

    _traverse_internals: _TraverseInternalsType = [
        ("element", InternalTraversal.dp_clauseelement)
    ]

    element: ColumnElement[_T]

    def __init__(self, element: ColumnElement[_T]):
        self.element = element
        self._propagate_attrs = element._propagate_attrs

    @util.ro_non_memoized_property
    def _from_objects(self) -> List[FromClause]:
        return []


class _textual_label_reference(ColumnElement[Any]):