Method reduce_columns

lib/sqlalchemy/sql/selectable.py:5990–6021

Return a new :func:`_expression.select` construct with redundantly named, equivalently-valued columns removed from the columns clause. "Redundant" here means two columns where one refers to the other either based on foreign key, or via a simple equality comparison in

(self, only_synonyms: bool = True)

    @util.preload_module("sqlalchemy.sql.util")
    def reduce_columns(self, only_synonyms: bool = True) -> Select[Any]:
        """Return a new :func:`_expression.select` construct with redundantly
        named, equivalently-valued columns removed from the columns clause.

        "Redundant" here means two columns where one refers to the
        other either based on foreign key, or via a simple equality
        comparison in the WHERE clause of the statement.   The primary purpose
        of this method is to automatically construct a select statement
        with all uniquely-named columns, without the need to use
        table-qualified labels as
        :meth:`_expression.Select.set_label_style`
        does.

        When columns are omitted based on foreign key, the referred-to
        column is the one that's kept.  When columns are omitted based on
        WHERE equivalence, the first column in the columns clause is the
        one that's kept.

        :param only_synonyms: when True, limit the removal of columns
         to those which have the same name as the equivalent.   Otherwise,
         all columns that are equivalent to another are removed.

        """
        woc: Select[Any]
        woc = self.with_only_columns(
            *util.preloaded.sql_util.reduce_columns(
                self._all_selected_columns,
                only_synonyms=only_synonyms,
                *(self._where_criteria + self._from_obj),
            )
        )
        return woc

    # START OVERLOADED FUNCTIONS self.with_only_columns Select 1-8 ", *, maintain_column_froms: bool =..." # noqa: E501