sqlalchemy.orm.query.Query

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Construct a :class:`_query.Query` directly. E.g.:: q = Query([User, Address], session=some_session) The above is equivalent to:: q = some_session.query(User, Address) :param entities: a sequence of entities and/or SQL expressions. :param session: a :class:`.Session` with which the :class:`_query.Query` will be associated. Optional; a :class:`_query.Query` can be associated with a :class:`.Session` generatively via the :meth:`_query.Query.with_session` method as well. .. seealso:: :meth:`.Session.query` :meth:`_query.Query.with_session`

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Add a column expression to the list of result columns to be returned.

Add one or more column expressions to the list of result columns to be returned. .. seealso:: :meth:`_sql.Select.add_columns` - v2 comparable method.

add a mapped entity to the list of result columns to be returned. .. seealso:: :meth:`_sql.Select.add_columns` - v2 comparable method.

Return the results represented by this :class:`_query.Query` as a list. This results in an execution of the underlying SQL statement. .. warning:: The :class:`_query.Query` object, when asked to return either a sequence or iterator that consists of full ORM-mapped entities, will **deduplicate entries based on primary key**. See the FAQ for more details. .. seealso:: :ref:`faq_query_deduplicating` .. seealso:: :meth:`_engine.Result.all` - v2 comparable method. :meth:`_engine.Result.scalars` - v2 comparable method.

Return the full SELECT statement represented by this :class:`_query.Query`, converted to a scalar subquery.

Return a Query with a specific 'autoflush' setting. As of SQLAlchemy 1.4, the :meth:`_orm.Query.autoflush` method is equivalent to using the ``autoflush`` execution option at the ORM level. See the section :ref:`orm_queryguide_autoflush` for further background on this option.

Return a :class:`.Query` construct which will correlate the given FROM clauses to that of an enclosing :class:`.Query` or :func:`~.expression.select`. The method here accepts mapped classes, :func:`.aliased` constructs, and :class:`_orm.Mapper` constructs as arguments, which are resolved into expression constructs, in addition to appropriate expression constructs. The correlation arguments are ultimately passed to :meth:`_expression.Select.correlate` after coercion to expression constructs. The correlation arguments take effect in such cases as when :meth:`_query.Query.from_self` is used, or when a subquery as returned by :meth:`_query.Query.subquery` is embedded in another :func:`_expression.select` construct. .. seealso:: :meth:`_sql.Select.correlate` - v2 equivalent method.

Return a count of rows this the SQL formed by this :class:`Query` would return. This generates the SQL for this Query as follows:: SELECT count(1) AS count_1 FROM ( SELECT <rest of query follows...> ) AS anon_1 The above SQL returns a single row, which is the aggregate value of the count function; the :meth:`_query.Query.count` method then returns that single integer value. .. warning:: It is important to note that the value returned by count() is **not the same as the number of ORM objects that this Query would return from a method such as the .all() method**. The :class:`_query.Query` object, when asked to return full entities, will **deduplicate entries based on primary key**, meaning if the same primary key value would appear in the results more than once, only one object of that primary key would be present. This does not apply to a query that is against individual columns. .. seealso:: :ref:`faq_query_deduplicating` For fine grained control over specific columns to count, to skip the usage of a subquery or otherwise control of the FROM clause, or to use other aggregate functions, use :attr:`~sqlalchemy.sql.expression.func` expressions in conjunction with :meth:`~.Session.query`, i.e.:: from sqlalchemy import func # count User records, without # using a subquery. session.query(func.count(User.id)) # return count of user "id" grouped # by "name" session.query(func.count(User.id)).\ group_by(User.name) from sqlalchemy import distinct # count distinct "name" values session.query(func.count(distinct(User.name))) .. seealso:: :ref:`migration_20_query_usage`

Return the full SELECT statement represented by this :class:`_query.Query` represented as a common table expression (CTE). Parameters and usage are the same as those of the :meth:`_expression.SelectBase.cte` method; see that method for further details. Here is the `PostgreSQL WITH RECURSIVE example <https://www.postgresql.org/docs/current/static/queries-with.html>`_. Note that, in this example, the ``included_parts`` cte and the ``incl_alias`` alias of it are Core selectables, which means the columns are accessed via the ``.c.`` attribute. The ``parts_alias`` object is an :func:`_orm.aliased` instance of the ``Part`` entity, so column-mapped attributes are available directly:: from sqlalchemy.orm import aliased class Part(Base): __tablename__ = 'part' part = Column(String, primary_key=True) sub_part = Column(String, primary_key=True) quantity = Column(Integer) included_parts = session.query( Part.sub_part, Part.part, Part.quantity).\ filter(Part.part=="our part").\ cte(name="included_parts", recursive=True) incl_alias = aliased(included_parts, name="pr") parts_alias = aliased(Part, name="p") included_parts = included_parts.union_all( session.query( parts_alias.sub_part, parts_alias.part, parts_alias.quantity).\ filter(parts_alias.part==incl_alias.c.sub_part) ) q = session.query( included_parts.c.sub_part, func.sum(included_parts.c.quantity). label('total_quantity') ).\ group_by(included_parts.c.sub_part) .. seealso:: :meth:`_sql.Select.cte` - v2 equivalent method.

Perform a DELETE with an arbitrary WHERE clause. Deletes rows matched by this query from the database. E.g.:: sess.query(User).filter(User.age == 25).\ delete(synchronize_session=False) sess.query(User).filter(User.age == 25).\ delete(synchronize_session='evaluate') .. warning:: See the section :ref:`orm_expression_update_delete` for important caveats and warnings, including limitations when using bulk UPDATE and DELETE with mapper inheritance configurations. :param synchronize_session: chooses the strategy to update the attributes on objects in the session. See the section :ref:`orm_expression_update_delete` for a discussion of these strategies. :return: the count of rows matched as returned by the database's "row count" feature. .. seealso:: :ref:`orm_expression_update_delete`

Apply a ``DISTINCT`` to the query and return the newly resulting ``Query``. .. note:: The ORM-level :meth:`.distinct` call includes logic that will automatically add columns from the ORDER BY of the query to the columns clause of the SELECT statement, to satisfy the common need of the database backend that ORDER BY columns be part of the SELECT list when DISTINCT is used. These columns *are not* added to the list of columns actually fetched by the :class:`_query.Query`, however, so would not affect results. The columns are passed through when using the :attr:`_query.Query.statement` accessor, however. .. deprecated:: 2.0 This logic is deprecated and will be removed in SQLAlchemy 2.0. See :ref:`migration_20_query_distinct` for a description of this use case in 2.0. .. seealso:: :meth:`_sql.Select.distinct` - v2 equivalent method. :param \*expr: optional column expressions. When present, the PostgreSQL dialect will render a ``DISTINCT ON (<expressions>)`` construct. .. deprecated:: 1.4 Using \*expr in other dialects is deprecated and will raise :class:`_exc.CompileError` in a future version.

Control whether assertions are generated. When set to False, the returned Query will not assert its state before certain operations, including that LIMIT/OFFSET has not been applied when filter() is called, no criterion exists when get() is called, and no "from_statement()" exists when filter()/order_by()/group_by() etc. is called. This more permissive mode is used by custom Query subclasses to specify criterion or other modifiers outside of the usual usage patterns. Care should be taken to ensure that the usage pattern is even possible. A statement applied by from_statement() will override any criterion set by filter() or order_by(), for example.

Control whether or not eager joins and subqueries are rendered. When set to False, the returned Query will not render eager joins regardless of :func:`~sqlalchemy.orm.joinedload`, :func:`~sqlalchemy.orm.subqueryload` options or mapper-level ``lazy='joined'``/``lazy='subquery'`` configurations. This is used primarily when nesting the Query's statement into a subquery or other selectable, or when using :meth:`_query.Query.yield_per`.

Produce an EXCEPT of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. .. seealso:: :meth:`_sql.Select.except_` - v2 equivalent method.

Produce an EXCEPT ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. .. seealso:: :meth:`_sql.Select.except_all` - v2 equivalent method.

Set non-SQL options which take effect during execution. Options allowed here include all of those accepted by :meth:`_engine.Connection.execution_options`, as well as a series of ORM specific options: ``populate_existing=True`` - equivalent to using :meth:`_orm.Query.populate_existing` ``autoflush=True|False`` - equivalent to using :meth:`_orm.Query.autoflush` ``yield_per=<value>`` - equivalent to using :meth:`_orm.Query.yield_per` Note that the ``stream_results`` execution option is enabled automatically if the :meth:`~sqlalchemy.orm.query.Query.yield_per()` method or execution option is used. .. versionadded:: 1.4 - added ORM options to :meth:`_orm.Query.execution_options` The execution options may also be specified on a per execution basis when using :term:`2.0 style` queries via the :paramref:`_orm.Session.execution_options` parameter. .. warning:: The :paramref:`_engine.Connection.execution_options.stream_results` parameter should not be used at the level of individual ORM statement executions, as the :class:`_orm.Session` will not track objects from different schema translate maps within a single session. For multiple schema translate maps within the scope of a single :class:`_orm.Session`, see :ref:`examples_sharding`. .. seealso:: :ref:`engine_stream_results` :meth:`_query.Query.get_execution_options` :meth:`_sql.Select.execution_options` - v2 equivalent method.

A convenience method that turns a query into an EXISTS subquery of the form EXISTS (SELECT 1 FROM ... WHERE ...). e.g.:: q = session.query(User).filter(User.name == 'fred') session.query(q.exists()) Producing SQL similar to:: SELECT EXISTS ( SELECT 1 FROM users WHERE users.name = :name_1 ) AS anon_1 The EXISTS construct is usually used in the WHERE clause:: session.query(User.id).filter(q.exists()).scalar() Note that some databases such as SQL Server don't allow an EXISTS expression to be present in the columns clause of a SELECT. To select a simple boolean value based on the exists as a WHERE, use :func:`.literal`:: from sqlalchemy import literal session.query(literal(True)).filter(q.exists()).scalar() .. seealso:: :meth:`_sql.Select.exists` - v2 comparable method.

Apply the given filtering criterion to a copy of this :class:`_query.Query`, using SQL expressions. e.g.:: session.query(MyClass).filter(MyClass.name == 'some name') Multiple criteria may be specified as comma separated; the effect is that they will be joined together using the :func:`.and_` function:: session.query(MyClass).\ filter(MyClass.name == 'some name', MyClass.id > 5) The criterion is any SQL expression object applicable to the WHERE clause of a select. String expressions are coerced into SQL expression constructs via the :func:`_expression.text` construct. .. seealso:: :meth:`_query.Query.filter_by` - filter on keyword expressions. :meth:`_sql.Select.where` - v2 equivalent method.

Apply the given filtering criterion to a copy of this :class:`_query.Query`, using keyword expressions. e.g.:: session.query(MyClass).filter_by(name = 'some name') Multiple criteria may be specified as comma separated; the effect is that they will be joined together using the :func:`.and_` function:: session.query(MyClass).\ filter_by(name = 'some name', id = 5) The keyword expressions are extracted from the primary entity of the query, or the last entity that was the target of a call to :meth:`_query.Query.join`. .. seealso:: :meth:`_query.Query.filter` - filter on SQL expressions. :meth:`_sql.Select.filter_by` - v2 comparable method.

Return the first result of this ``Query`` or None if the result doesn't contain any row. first() applies a limit of one within the generated SQL, so that only one primary entity row is generated on the server side (note this may consist of multiple result rows if join-loaded collections are present). Calling :meth:`_query.Query.first` results in an execution of the underlying query. .. seealso:: :meth:`_query.Query.one` :meth:`_query.Query.one_or_none` :meth:`_engine.Result.first` - v2 comparable method. :meth:`_engine.Result.scalars` - v2 comparable method.

Execute the given SELECT statement and return results. This method bypasses all internal statement compilation, and the statement is executed without modification. The statement is typically either a :func:`_expression.text` or :func:`_expression.select` construct, and should return the set of columns appropriate to the entity class represented by this :class:`_query.Query`. .. seealso:: :meth:`_sql.Select.from_statement` - v2 comparable method.

Return an instance based on the given primary key identifier, or ``None`` if not found. E.g.:: my_user = session.query(User).get(5) some_object = session.query(VersionedFoo).get((5, 10)) some_object = session.query(VersionedFoo).get( {"id": 5, "version_id": 10}) :meth:`_query.Query.get` is special in that it provides direct access to the identity map of the owning :class:`.Session`. If the given primary key identifier is present in the local identity map, the object is returned directly from this collection and no SQL is emitted, unless the object has been marked fully expired. If not present, a SELECT is performed in order to locate the object. :meth:`_query.Query.get` also will perform a check if the object is present in the identity map and marked as expired - a SELECT is emitted to refresh the object as well as to ensure that the row is still present. If not, :class:`~sqlalchemy.orm.exc.ObjectDeletedError` is raised. :meth:`_query.Query.get` is only used to return a single mapped instance, not multiple instances or individual column constructs, and strictly on a single primary key value. The originating :class:`_query.Query` must be constructed in this way, i.e. against a single mapped entity, with no additional filtering criterion. Loading options via :meth:`_query.Query.options` may be applied however, and will be used if the object is not yet locally present. :param ident: A scalar, tuple, or dictionary representing the primary key. For a composite (e.g. multiple column) primary key, a tuple or dictionary should be passed. For a single-column primary key, the scalar calling form is typically the most expedient. If the primary key of a row is the value "5", the call looks like:: my_object = query.get(5) The tuple form contains primary key values typically in the order in which they correspond to the mapped :class:`_schema.Table` object's primary key columns, or if the :paramref:`_orm.Mapper.primary_key` configuration parameter were used, in the order used for that parameter. For example, if the primary key of a row is represented by the integer digits "5, 10" the call would look like:: my_object = query.get((5, 10)) The dictionary form should include as keys the mapped attribute names corresponding to each element of the primary key. If the mapped class has the attributes ``id``, ``version_id`` as the attributes which store the object's primary key value, the call would look like:: my_object = query.get({"id": 5, "version_id": 10}) .. versionadded:: 1.3 the :meth:`_query.Query.get` method now optionally accepts a dictionary of attribute names to values in order to indicate a primary key identifier. :return: The object instance, or ``None``.

Get the non-SQL options which will take effect during execution. .. versionadded:: 1.3 .. seealso:: :meth:`_query.Query.execution_options` :meth:`_sql.Select.get_execution_options` - v2 comparable method.

Apply one or more GROUP BY criterion to the query and return the newly resulting :class:`_query.Query`. All existing GROUP BY settings can be suppressed by passing ``None`` - this will suppress any GROUP BY configured on mappers as well. .. seealso:: These sections describe GROUP BY in terms of :term:`2.0 style` invocation but apply to :class:`_orm.Query` as well: :ref:`tutorial_group_by_w_aggregates` - in the :ref:`unified_tutorial` :ref:`tutorial_order_by_label` - in the :ref:`unified_tutorial` :meth:`_sql.Select.group_by` - v2 equivalent method.

Apply a HAVING criterion to the query and return the newly resulting :class:`_query.Query`. :meth:`_query.Query.having` is used in conjunction with :meth:`_query.Query.group_by`. HAVING criterion makes it possible to use filters on aggregate functions like COUNT, SUM, AVG, MAX, and MIN, eg.:: q = session.query(User.id).\ join(User.addresses).\ group_by(User.id).\ having(func.count(Address.id) > 2) .. seealso:: :meth:`_sql.Select.having` - v2 equivalent method.

Return an ORM result given a :class:`_engine.CursorResult` and :class:`.QueryContext`.

Produce an INTERSECT of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. .. seealso:: :meth:`_sql.Select.intersect` - v2 equivalent method.

Produce an INTERSECT ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. .. seealso:: :meth:`_sql.Select.intersect_all` - v2 equivalent method.

Create a SQL JOIN against this :class:`_query.Query` object's criterion and apply generatively, returning the newly resulting :class:`_query.Query`. **Simple Relationship Joins** Consider a mapping between two classes ``User`` and ``Address``, with a relationship ``User.addresses`` representing a collection of ``Address`` objects associated with each ``User``. The most common usage of :meth:`_query.Query.join` is to create a JOIN along this relationship, using the ``User.addresses`` attribute as an indicator for how this should occur:: q = session.query(User).join(User.addresses) Where above, the call to :meth:`_query.Query.join` along ``User.addresses`` will result in SQL approximately equivalent to:: SELECT user.id, user.name FROM user JOIN address ON user.id = address.user_id In the above example we refer to ``User.addresses`` as passed to :meth:`_query.Query.join` as the "on clause", that is, it indicates how the "ON" portion of the JOIN should be constructed. To construct a chain of joins, multiple :meth:`_query.Query.join` calls may be used. The relationship-bound attribute implies both the left and right side of the join at once:: q = session.query(User).\ join(User.orders).\ join(Order.items).\ join(Item.keywords) .. note:: as seen in the above example, **the order in which each call to the join() method occurs is important**. Query would not, for example, know how to join correctly if we were to specify ``User``, then ``Item``, then ``Order``, in our chain of joins; in such a case, depending on the arguments passed, it may raise an error that it doesn't know how to join, or it may produce invalid SQL in which case the database will raise an error. In correct practice, the :meth:`_query.Query.join` method is invoked in such a way that lines up with how we would want the JOIN clauses in SQL to be rendered, and each call should represent a clear link from what precedes it. **Joins to a Target Entity or Selectable** A second form of :meth:`_query.Query.join` allows any mapped entity or core selectable construct as a target. In this usage, :meth:`_query.Query.join` will attempt to create a JOIN along the natural foreign key relationship between two entities:: q = session.query(User).join(Address) In the above calling form, :meth:`_query.Query.join` is called upon to create the "on clause" automatically for us. This calling form will ultimately raise an error if either there are no foreign keys between the two entities, or if there are multiple foreign key linkages between the target entity and the entity or entities already present on the left side such that creating a join requires more information. Note that when indicating a join to a target without any ON clause, ORM configured relationships are not taken into account. **Joins to a Target with an ON Clause** The third calling form allows both the target entity as well as the ON clause to be passed explicitly. A example that includes a SQL expression as the ON clause is as follows:: q = session.query(User).join(Address, User.id==Address.user_id) The above form may also use a relationship-bound attribute as the ON clause as well:: q = session.query(User).join(Address, User.addresses) The above syntax can be useful for the case where we wish to join to an alias of a particular target entity. If we wanted to join to ``Address`` twice, it could be achieved using two aliases set up using the :func:`~sqlalchemy.orm.aliased` function:: a1 = aliased(Address) a2 = aliased(Address) q = session.query(User).\ join(a1, User.addresses).\ join(a2, User.addresses).\ filter(a1.email_address=='ed@foo.com').\ filter(a2.email_address=='ed@bar.com') The relationship-bound calling form can also specify a target entity using the :meth:`_orm.PropComparator.of_type` method; a query equivalent to the one above would be:: a1 = aliased(Address) a2 = aliased(Address) q = session.query(User).\ join(User.addresses.of_type(a1)).\ join(User.addresses.of_type(a2)).\ filter(a1.email_address == 'ed@foo.com').\ filter(a2.email_address == 'ed@bar.com') **Augmenting Built-in ON Clauses** As a substitute for providing a full custom ON condition for an existing relationship, the :meth:`_orm.PropComparator.and_` function may be applied to a relationship attribute to augment additional criteria into the ON clause; the additional criteria will be combined with the default criteria using AND:: q = session.query(User).join( User.addresses.and_(Address.email_address != 'foo@bar.com') ) .. versionadded:: 1.4 **Joining to Tables and Subqueries** The target of a join may also be any table or SELECT statement, which may be related to a target entity or not. Use the appropriate ``.subquery()`` method in order to make a subquery out of a query:: subq = session.query(Address).\ filter(Address.email_address == 'ed@foo.com').\ subquery() q = session.query(User).join( subq, User.id == subq.c.user_id ) Joining to a subquery in terms of a specific relationship and/or target entity may be achieved by linking the subquery to the entity using :func:`_orm.aliased`:: subq = session.query(Address).\ filter(Address.email_address == 'ed@foo.com').\ subquery() address_subq = aliased(Address, subq) q = session.query(User).join( User.addresses.of_type(address_subq) ) **Controlling what to Join From** In cases where the left side of the current state of :class:`_query.Query` is not in line with what we want to join from, the :meth:`_query.Query.select_from` method may be used:: q = session.query(Address).select_from(User).\ join(User.addresses).\ filter(User.name == 'ed') Which will produce SQL similar to:: SELECT address.* FROM user JOIN address ON user.id=address.user_id WHERE user.name = :name_1 .. seealso:: :meth:`_sql.Select.join` - v2 equivalent method. :param \*props: Incoming arguments for :meth:`_query.Query.join`, the props collection in modern use should be considered to be a one or two argument form, either as a single "target" entity or ORM attribute-bound relationship, or as a target entity plus an "on clause" which may be a SQL expression or ORM attribute-bound relationship. :param isouter=False: If True, the join used will be a left outer join, just as if the :meth:`_query.Query.outerjoin` method were called. :param full=False: render FULL OUTER JOIN; implies ``isouter``. .. versionadded:: 1.1

Return the full SELECT statement represented by this :class:`_query.Query`, converted to a scalar subquery with a label of the given name. .. seealso:: :meth:`_sql.Select.label` - v2 comparable method.

Apply a ``LIMIT`` to the query and return the newly resulting ``Query``. .. seealso:: :meth:`_sql.Select.limit` - v2 equivalent method.

Merge a result into this :class:`_query.Query` object's Session. Given an iterator returned by a :class:`_query.Query` of the same structure as this one, return an identical iterator of results, with all mapped instances merged into the session using :meth:`.Session.merge`. This is an optimized method which will merge all mapped instances, preserving the structure of the result rows and unmapped columns with less method overhead than that of calling :meth:`.Session.merge` explicitly for each value. The structure of the results is determined based on the column list of this :class:`_query.Query` - if these do not correspond, unchecked errors will occur. The 'load' argument is the same as that of :meth:`.Session.merge`. For an example of how :meth:`_query.Query.merge_result` is used, see the source code for the example :ref:`examples_caching`, where :meth:`_query.Query.merge_result` is used to efficiently restore state from a cache back into a target :class:`.Session`.

Apply an ``OFFSET`` to the query and return the newly resulting ``Query``. .. seealso:: :meth:`_sql.Select.offset` - v2 equivalent method.

Return exactly one result or raise an exception. Raises ``sqlalchemy.orm.exc.NoResultFound`` if the query selects no rows. Raises ``sqlalchemy.orm.exc.MultipleResultsFound`` if multiple object identities are returned, or if multiple rows are returned for a query that returns only scalar values as opposed to full identity-mapped entities. Calling :meth:`.one` results in an execution of the underlying query. .. seealso:: :meth:`_query.Query.first` :meth:`_query.Query.one_or_none` :meth:`_engine.Result.one` - v2 comparable method. :meth:`_engine.Result.scalar_one` - v2 comparable method.

Return at most one result or raise an exception. Returns ``None`` if the query selects no rows. Raises ``sqlalchemy.orm.exc.MultipleResultsFound`` if multiple object identities are returned, or if multiple rows are returned for a query that returns only scalar values as opposed to full identity-mapped entities. Calling :meth:`_query.Query.one_or_none` results in an execution of the underlying query. .. versionadded:: 1.0.9 Added :meth:`_query.Query.one_or_none` .. seealso:: :meth:`_query.Query.first` :meth:`_query.Query.one` :meth:`_engine.Result.one_or_none` - v2 comparable method. :meth:`_engine.Result.scalar_one_or_none` - v2 comparable method.

When set to True, the query results will always be a :class:`.Row` object. This can change a query that normally returns a single entity as a scalar to return a :class:`.Row` result in all cases. .. seealso:: :meth:`.Query.tuples` - returns tuples, but also at the typing level will type results as ``Tuple``. :meth:`_query.Query.is_single_entity` :meth:`_engine.Result.tuples` - v2 comparable method.

Return a new :class:`_query.Query` object, applying the given list of mapper options. Most supplied options regard changing how column- and relationship-mapped attributes are loaded. .. seealso:: :ref:`loading_columns` :ref:`relationship_loader_options`

Apply one or more ORDER BY criteria to the query and return the newly resulting :class:`_query.Query`. e.g.:: q = session.query(Entity).order_by(Entity.id, Entity.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 q = q.order_by(None).order_by(new_col) .. seealso:: These sections describe ORDER BY in terms of :term:`2.0 style` invocation but apply to :class:`_orm.Query` as well: :ref:`tutorial_order_by` - in the :ref:`unified_tutorial` :ref:`tutorial_order_by_label` - in the :ref:`unified_tutorial` :meth:`_sql.Select.order_by` - v2 equivalent method.

Create a left outer join against this ``Query`` object's criterion and apply generatively, returning the newly resulting ``Query``. Usage is the same as the ``join()`` method. .. seealso:: :meth:`_sql.Select.outerjoin` - v2 equivalent method.

Add values for bind parameters which may have been specified in filter(). Parameters may be specified using \**kwargs, or optionally a single dictionary as the first positional argument. The reason for both is that \**kwargs is convenient, however some parameter dictionaries contain unicode keys in which case \**kwargs cannot be used.

Return a :class:`_query.Query` that will expire and refresh all instances as they are loaded, or reused from the current :class:`.Session`. As of SQLAlchemy 1.4, the :meth:`_orm.Query.populate_existing` method is equivalent to using the ``populate_existing`` execution option at the ORM level. See the section :ref:`orm_queryguide_populate_existing` for further background on this option.

Return a new :class:`.Query`, where the "join point" has been reset back to the base FROM entities of the query. This method is usually used in conjunction with the ``aliased=True`` feature of the :meth:`~.Query.join` method. See the example in :meth:`~.Query.join` for how this is used.

Return the first element of the first result or None if no rows present. If multiple rows are returned, raises MultipleResultsFound. >>> session.query(Item).scalar() <Item> >>> session.query(Item.id).scalar() 1 >>> session.query(Item.id).filter(Item.id < 0).scalar() None >>> session.query(Item.id, Item.name).scalar() 1 >>> session.query(func.count(Parent.id)).scalar() 20 This results in an execution of the underlying query. .. seealso:: :meth:`_engine.Result.scalar` - v2 comparable method.

Return the full SELECT statement represented by this :class:`_query.Query`, converted to a scalar subquery. Analogous to :meth:`sqlalchemy.sql.expression.SelectBase.scalar_subquery`. .. versionchanged:: 1.4 The :meth:`_query.Query.scalar_subquery` method replaces the :meth:`_query.Query.as_scalar` method. .. seealso:: :meth:`_sql.Select.scalar_subquery` - v2 comparable method.

Set the FROM clause of this :class:`.Query` explicitly. :meth:`.Query.select_from` is often used in conjunction with :meth:`.Query.join` in order to control which entity is selected from on the "left" side of the join. The entity or selectable object here effectively replaces the "left edge" of any calls to :meth:`~.Query.join`, when no joinpoint is otherwise established - usually, the default "join point" is the leftmost entity in the :class:`~.Query` object's list of entities to be selected. A typical example:: q = session.query(Address).select_from(User).\ join(User.addresses).\ filter(User.name == 'ed') Which produces SQL equivalent to:: SELECT address.* FROM user JOIN address ON user.id=address.user_id WHERE user.name = :name_1 :param \*from_obj: collection of one or more entities to apply to the FROM clause. Entities can be mapped classes, :class:`.AliasedClass` objects, :class:`.Mapper` objects as well as core :class:`.FromClause` elements like subqueries. .. versionchanged:: 0.9 This method no longer applies the given FROM object to be the selectable from which matching entities select from; the :meth:`.select_entity_from` method now accomplishes this. See that method for a description of this behavior. .. seealso:: :meth:`~.Query.join` :meth:`.Query.select_entity_from` :meth:`_sql.Select.select_from` - v2 equivalent method.

Apply column labels to the return value of Query.statement. Indicates that this Query's `statement` accessor should return a SELECT statement that applies labels to all columns in the form <tablename>_<columnname>; this is commonly used to disambiguate columns from multiple tables which have the same name. When the `Query` actually issues SQL to load rows, it always uses column labeling. .. note:: The :meth:`_query.Query.set_label_style` method *only* applies the output of :attr:`_query.Query.statement`, and *not* to any of the result-row invoking systems of :class:`_query.Query` itself, e.g. :meth:`_query.Query.first`, :meth:`_query.Query.all`, etc. To execute a query using :meth:`_query.Query.set_label_style`, invoke the :attr:`_query.Query.statement` using :meth:`.Session.execute`:: result = session.execute( query .set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL) .statement ) .. versionadded:: 1.4 .. seealso:: :meth:`_sql.Select.set_label_style` - v2 equivalent method.

Computes the "slice" of the :class:`_query.Query` represented by the given indices and returns the resulting :class:`_query.Query`. 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, :: session.query(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) .. seealso:: :meth:`_query.Query.limit` :meth:`_query.Query.offset` :meth:`_sql.Select.slice` - v2 equivalent method.

Return the full SELECT statement represented by this :class:`_query.Query`, embedded within an :class:`_expression.Alias`. Eager JOIN generation within the query is disabled. .. seealso:: :meth:`_sql.Select.subquery` - v2 comparable method. :param name: string name to be assigned as the alias; this is passed through to :meth:`_expression.FromClause.alias`. If ``None``, a name will be deterministically generated at compile time. :param with_labels: if True, :meth:`.with_labels` will be called on the :class:`_query.Query` first to apply table-qualified labels to all columns. :param reduce_columns: if True, :meth:`_expression.Select.reduce_columns` will be called on the resulting :func:`_expression.select` construct, to remove same-named columns where one also refers to the other via foreign key or WHERE clause equivalence.

return a tuple-typed form of this :class:`.Query`. This method invokes the :meth:`.Query.only_return_tuples` method with a value of ``True``, which by itself ensures that this :class:`.Query` will always return :class:`.Row` objects, even if the query is made against a single entity. It then also at the typing level will return a "typed" query, if possible, that will type result rows as ``Tuple`` objects with typed elements. This method can be compared to the :meth:`.Result.tuples` method, which returns "self", but from a typing perspective returns an object that will yield typed ``Tuple`` objects for results. Typing takes effect only if this :class:`.Query` object is a typed query object already. .. versionadded:: 2.0 .. seealso:: :meth:`.Result.tuples` - v2 equivalent method.

Produce a UNION of this Query against one or more queries. e.g.:: q1 = sess.query(SomeClass).filter(SomeClass.foo=='bar') q2 = sess.query(SomeClass).filter(SomeClass.bar=='foo') q3 = q1.union(q2) The method accepts multiple Query objects so as to control the level of nesting. A series of ``union()`` calls such as:: x.union(y).union(z).all() will nest on each ``union()``, and produces:: SELECT * FROM (SELECT * FROM (SELECT * FROM X UNION SELECT * FROM y) UNION SELECT * FROM Z) Whereas:: x.union(y, z).all() produces:: SELECT * FROM (SELECT * FROM X UNION SELECT * FROM y UNION SELECT * FROM Z) Note that many database backends do not allow ORDER BY to be rendered on a query called within UNION, EXCEPT, etc. To disable all ORDER BY clauses including those configured on mappers, issue ``query.order_by(None)`` - the resulting :class:`_query.Query` object will not render ORDER BY within its SELECT statement. .. seealso:: :meth:`_sql.Select.union` - v2 equivalent method.

Produce a UNION ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. .. seealso:: :meth:`_sql.Select.union_all` - v2 equivalent method.

Perform an UPDATE with an arbitrary WHERE clause. Updates rows matched by this query in the database. E.g.:: sess.query(User).filter(User.age == 25).\ update({User.age: User.age - 10}, synchronize_session=False) sess.query(User).filter(User.age == 25).\ update({"age": User.age - 10}, synchronize_session='evaluate') .. warning:: See the section :ref:`orm_expression_update_delete` for important caveats and warnings, including limitations when using arbitrary UPDATE and DELETE with mapper inheritance configurations. :param values: a dictionary with attributes names, or alternatively mapped attributes or SQL expressions, as keys, and literal values or sql expressions as values. If :ref:`parameter-ordered mode <tutorial_parameter_ordered_updates>` is desired, the values can be passed as a list of 2-tuples; this requires that the :paramref:`~sqlalchemy.sql.expression.update.preserve_parameter_order` flag is passed to the :paramref:`.Query.update.update_args` dictionary as well. :param synchronize_session: chooses the strategy to update the attributes on objects in the session. See the section :ref:`orm_expression_update_delete` for a discussion of these strategies. :param update_args: Optional dictionary, if present will be passed to the underlying :func:`_expression.update` construct as the ``**kw`` for the object. May be used to pass dialect-specific arguments such as ``mysql_limit``, as well as other special arguments such as :paramref:`~sqlalchemy.sql.expression.update.preserve_parameter_order`. :return: the count of rows matched as returned by the database's "row count" feature. .. seealso:: :ref:`orm_expression_update_delete`

Return a scalar result corresponding to the given column expression.

Return an iterator yielding result tuples corresponding to the given list of columns

A synonym for :meth:`.Query.filter`. .. versionadded:: 1.4 .. seealso:: :meth:`_sql.Select.where` - v2 equivalent method.

Return a new :class:`_query.Query` replacing the SELECT list with the given entities. e.g.:: # Users, filtered on some arbitrary criterion # and then ordered by related email address q = session.query(User).\ join(User.address).\ filter(User.name.like('%ed%')).\ order_by(Address.email) # given *only* User.id==5, Address.email, and 'q', what # would the *next* User in the result be ? subq = q.with_entities(Address.email).\ order_by(None).\ filter(User.id==5).\ subquery() q = q.join((subq, subq.c.email < Address.email)).\ limit(1) .. seealso:: :meth:`_sql.Select.with_only_columns` - v2 comparable method.

return a new :class:`_query.Query` with the specified options for the ``FOR UPDATE`` clause. The behavior of this method is identical to that of :meth:`_expression.GenerativeSelect.with_for_update`. When called with no arguments, the resulting ``SELECT`` statement will have a ``FOR UPDATE`` clause appended. When additional arguments are specified, backend-specific options such as ``FOR UPDATE NOWAIT`` or ``LOCK IN SHARE MODE`` can take effect. E.g.:: q = sess.query(User).populate_existing().with_for_update(nowait=True, of=User) The above query on a PostgreSQL backend will render like:: SELECT users.id AS users_id FROM users FOR UPDATE OF users NOWAIT .. warning:: Using ``with_for_update`` in the context of eager loading relationships is not officially supported or recommended by SQLAlchemy and may not work with certain queries on various database backends. When ``with_for_update`` is successfully used with a query that involves :func:`_orm.joinedload`, SQLAlchemy will attempt to emit SQL that locks all involved tables. .. note:: It is generally a good idea to combine the use of the :meth:`_orm.Query.populate_existing` method when using the :meth:`_orm.Query.with_for_update` method. The purpose of :meth:`_orm.Query.populate_existing` is to force all the data read from the SELECT to be populated into the ORM objects returned, even if these objects are already in the :term:`identity map`. .. seealso:: :meth:`_expression.GenerativeSelect.with_for_update` - Core level method with full argument and behavioral description. :meth:`_orm.Query.populate_existing` - overwrites attributes of objects already loaded in the identity map.

Undocumented

Add filtering criterion that relates the given instance to a child object or collection, using its attribute state as well as an established :func:`_orm.relationship()` configuration. The method uses the :func:`.with_parent` function to generate the clause, the result of which is passed to :meth:`_query.Query.filter`. Parameters are the same as :func:`.with_parent`, with the exception that the given property can be None, in which case a search is performed against this :class:`_query.Query` object's target mapper. :param instance: An instance which has some :func:`_orm.relationship`. :param property: Class bound attribute which indicates what relationship from the instance should be used to reconcile the parent/child relationship. :param from_entity: Entity in which to consider as the left side. This defaults to the "zero" entity of the :class:`_query.Query` itself.

Return a :class:`_query.Query` that will use the given :class:`.Session`. While the :class:`_query.Query` object is normally instantiated using the :meth:`.Session.query` method, it is legal to build the :class:`_query.Query` directly without necessarily using a :class:`.Session`. Such a :class:`_query.Query` object, or any :class:`_query.Query` already associated with a different :class:`.Session`, can produce a new :class:`_query.Query` object associated with a target session using this method:: from sqlalchemy.orm import Query query = Query([MyClass]).filter(MyClass.id == 5) result = query.with_session(my_session).one()

Return a new :class:`_query.Query` object transformed by the given function. E.g.:: def filter_something(criterion): def transform(q): return q.filter(criterion) return transform q = q.with_transformation(filter_something(x==5)) This allows ad-hoc recipes to be created for :class:`_query.Query` objects.

Yield only ``count`` rows at a time. The purpose of this method is when fetching very large result sets (> 10K rows), to batch results in sub-collections and yield them out partially, so that the Python interpreter doesn't need to declare very large areas of memory which is both time consuming and leads to excessive memory use. The performance from fetching hundreds of thousands of rows can often double when a suitable yield-per setting (e.g. approximately 1000) is used, even with DBAPIs that buffer rows (which are most). As of SQLAlchemy 1.4, the :meth:`_orm.Query.yield_per` method is equivalent to using the ``yield_per`` execution option at the ORM level. See the section :ref:`orm_queryguide_yield_per` for further background on this option. .. seealso:: :ref:`orm_queryguide_yield_per`