sqlalchemy.sql.selectable.GenerativeSelect

Undocumented

Return a new selectable with the given FETCH FIRST criterion applied. This is a numeric value which usually renders as ``FETCH {FIRST | NEXT} [ count ] {ROW | ROWS} {ONLY | WITH TIES}`` expression in the resulting select. This functionality is is currently implemented for Oracle, PostgreSQL, MSSQL. Use :meth:`_sql.GenerativeSelect.offset` to specify the offset. .. note:: The :meth:`_sql.GenerativeSelect.fetch` method will replace any clause applied with :meth:`_sql.GenerativeSelect.limit`. .. versionadded:: 1.4 :param count: an integer COUNT parameter, or a SQL expression that provides an integer result. When ``percent=True`` this will represent the percentage of rows to return, not the absolute value. Pass ``None`` to reset it. :param with_ties: When ``True``, the WITH TIES option is used to return any additional rows that tie for the last place in the result set according to the ``ORDER BY`` clause. The ``ORDER BY`` may be mandatory in this case. Defaults to ``False`` :param percent: When ``True``, ``count`` represents the percentage of the total number of selected rows to return. Defaults to ``False`` .. seealso:: :meth:`_sql.GenerativeSelect.limit` :meth:`_sql.GenerativeSelect.offset`

Retrieve the current label style. .. versionadded:: 1.4

Return a new selectable with the given list of GROUP BY criterion applied. All existing GROUP BY settings can be suppressed by passing ``None``. e.g.:: stmt = select(table.c.name, func.max(table.c.stat)).\ group_by(table.c.name) :param \*clauses: a series of :class:`_expression.ColumnElement` constructs which will be used to generate an GROUP BY clause. .. seealso:: :ref:`tutorial_group_by_w_aggregates` - in the :ref:`unified_tutorial` :ref:`tutorial_order_by_label` - in the :ref:`unified_tutorial`

Return a new selectable with the given LIMIT criterion applied. This is a numerical value which usually renders as a ``LIMIT`` expression in the resulting select. Backends that don't support ``LIMIT`` will attempt to provide similar functionality. .. note:: The :meth:`_sql.GenerativeSelect.limit` method will replace any clause applied with :meth:`_sql.GenerativeSelect.fetch`. .. versionchanged:: 1.0.0 - :meth:`_expression.Select.limit` can now accept arbitrary SQL expressions as well as integer values. :param limit: an integer LIMIT parameter, or a SQL expression that provides an integer result. Pass ``None`` to reset it. .. seealso:: :meth:`_sql.GenerativeSelect.fetch` :meth:`_sql.GenerativeSelect.offset`

Return a new selectable with the given OFFSET criterion applied. This is a numeric value which usually renders as an ``OFFSET`` expression in the resulting select. Backends that don't support ``OFFSET`` will attempt to provide similar functionality. .. versionchanged:: 1.0.0 - :meth:`_expression.Select.offset` can now accept arbitrary SQL expressions as well as integer values. :param offset: an integer OFFSET parameter, or a SQL expression that provides an integer result. Pass ``None`` to reset it. .. seealso:: :meth:`_sql.GenerativeSelect.limit` :meth:`_sql.GenerativeSelect.fetch`

Return a new selectable with the given list of ORDER BY criteria applied. e.g.:: stmt = select(table).order_by(table.c.id, table.c.name) Calling this method multiple times is equivalent to calling it once with all the clauses concatenated. All existing ORDER BY criteria may be cancelled by passing ``None`` by itself. New ORDER BY criteria may then be added by invoking :meth:`_orm.Query.order_by` again, e.g.:: # will erase all ORDER BY and ORDER BY new_col alone stmt = stmt.order_by(None).order_by(new_col) :param \*clauses: a series of :class:`_expression.ColumnElement` constructs which will be used to generate an ORDER BY clause. .. seealso:: :ref:`tutorial_order_by` - in the :ref:`unified_tutorial` :ref:`tutorial_order_by_label` - in the :ref:`unified_tutorial`

Return a new selectable with the specified label style. There are three "label styles" available, :attr:`_sql.SelectLabelStyle.LABEL_STYLE_DISAMBIGUATE_ONLY`, :attr:`_sql.SelectLabelStyle.LABEL_STYLE_TABLENAME_PLUS_COL`, and :attr:`_sql.SelectLabelStyle.LABEL_STYLE_NONE`. The default style is :attr:`_sql.SelectLabelStyle.LABEL_STYLE_TABLENAME_PLUS_COL`. In modern SQLAlchemy, there is not generally a need to change the labeling style, as per-expression labels are more effectively used by making use of the :meth:`_sql.ColumnElement.label` method. In past versions, :data:`_sql.LABEL_STYLE_TABLENAME_PLUS_COL` was used to disambiguate same-named columns from different tables, aliases, or subqueries; the newer :data:`_sql.LABEL_STYLE_DISAMBIGUATE_ONLY` now applies labels only to names that conflict with an existing name so that the impact of this labeling is minimal. The rationale for disambiguation is mostly so that all column expressions are available from a given :attr:`_sql.FromClause.c` collection when a subquery is created. .. versionadded:: 1.4 - the :meth:`_sql.GenerativeSelect.set_label_style` method replaces the previous combination of ``.apply_labels()``, ``.with_labels()`` and ``use_labels=True`` methods and/or parameters. .. seealso:: :data:`_sql.LABEL_STYLE_DISAMBIGUATE_ONLY` :data:`_sql.LABEL_STYLE_TABLENAME_PLUS_COL` :data:`_sql.LABEL_STYLE_NONE` :data:`_sql.LABEL_STYLE_DEFAULT`

Apply LIMIT / OFFSET to this statement based on a slice. The start and stop indices behave like the argument to Python's built-in :func:`range` function. This method provides an alternative to using ``LIMIT``/``OFFSET`` to get a slice of the query. For example, :: stmt = select(User).order_by(User).id.slice(1, 3) renders as .. sourcecode:: sql SELECT users.id AS users_id, users.name AS users_name FROM users ORDER BY users.id LIMIT ? OFFSET ? (2, 1) .. note:: The :meth:`_sql.GenerativeSelect.slice` method will replace any clause applied with :meth:`_sql.GenerativeSelect.fetch`. .. versionadded:: 1.4 Added the :meth:`_sql.GenerativeSelect.slice` method generalized from the ORM. .. seealso:: :meth:`_sql.GenerativeSelect.limit` :meth:`_sql.GenerativeSelect.offset` :meth:`_sql.GenerativeSelect.fetch`

Specify a ``FOR UPDATE`` clause for this :class:`_expression.GenerativeSelect`. E.g.:: stmt = select(table).with_for_update(nowait=True) On a database like PostgreSQL or Oracle, the above would render a statement like:: SELECT table.a, table.b FROM table FOR UPDATE NOWAIT on other backends, the ``nowait`` option is ignored and instead would produce:: SELECT table.a, table.b FROM table FOR UPDATE When called with no arguments, the statement will render with the suffix ``FOR UPDATE``. Additional arguments can then be provided which allow for common database-specific variants. :param nowait: boolean; will render ``FOR UPDATE NOWAIT`` on Oracle and PostgreSQL dialects. :param read: boolean; will render ``LOCK IN SHARE MODE`` on MySQL, ``FOR SHARE`` on PostgreSQL. On PostgreSQL, when combined with ``nowait``, will render ``FOR SHARE NOWAIT``. :param of: SQL expression or list of SQL expression elements, (typically :class:`_schema.Column` objects or a compatible expression, for some backends may also be a table expression) which will render into a ``FOR UPDATE OF`` clause; supported by PostgreSQL, Oracle, some MySQL versions and possibly others. May render as a table or as a column depending on backend. :param skip_locked: boolean, will render ``FOR UPDATE SKIP LOCKED`` on Oracle and PostgreSQL dialects or ``FOR SHARE SKIP LOCKED`` if ``read=True`` is also specified. :param key_share: boolean, will render ``FOR NO KEY UPDATE``, or if combined with ``read=True`` will render ``FOR KEY SHARE``, on the PostgreSQL dialect.