Release: 2.0.31 | Release Date: June 18, 2024

# SQLAlchemy 2.0 Documentation

ORM Querying Guide

This page is part of the ORM Querying Guide.

Previous: ORM API Features for Querying

# Legacy Query API

About the Legacy Query API

This page contains the Python generated documentation for the `Query` construct, which for many years was the sole SQL interface when working with the SQLAlchemy ORM. As of version 2.0, an all new way of working is now the standard approach, where the same `select()` construct that works for Core works just as well for the ORM, providing a consistent interface for building queries.

For any application that is built on the SQLAlchemy ORM prior to the 2.0 API, the `Query` API will usually represents the vast majority of database access code within an application, and as such the majority of the `Query` API is not being removed from SQLAlchemy. The `Query` object behind the scenes now translates itself into a 2.0 style `select()` object when the `Query` object is executed, so it now is just a very thin adapter API.

For a guide to migrating an application based on `Query` to 2.0 style, see 2.0 Migration - ORM Usage.

For an introduction to writing SQL for ORM objects in the 2.0 style, start with the SQLAlchemy Unified Tutorial. Additional reference for 2.0 style querying is at ORM Querying Guide.

## The Query Object

`Query` is produced in terms of a given `Session`, using the `Session.query()` method:

    q = session.query(SomeMappedClass)

Following is the full interface for the `Query` object.

Object Name | Description
--- | ---
Query | ORM-level SQL construction object.

class sqlalchemy.orm.Query

  ORM-level SQL construction object.

  Legacy Feature

  The ORM `Query` object is a legacy construct as of SQLAlchemy 2.0. See the notes at the top of Legacy Query API for an overview, including links to migration documentation.

  `Query` objects are normally initially generated using the `Session.query()` method of `Session`, and in less common cases by instantiating the `Query` directly and associating with a `Session` using the `Query.with_session()` method.

  Members

  __init__(), add_column(), add_columns(), add_entity(), all(), apply_labels(), as_scalar(), autoflush(), column_descriptions, correlate(), count(), cte(), delete(), distinct(), enable_assertions(), enable_eagerloads(), except_(), except_all(), execution_options(), exists(), filter(), filter_by(), first(), from_statement(), get(), get_children(), get_execution_options(), get_label_style, group_by(), having(), instances(), intersect(), intersect_all(), is_single_entity, join(), label(), lazy_loaded_from, limit(), merge_result(), offset(), one(), one_or_none(), only_return_tuples(), options(), order_by(), outerjoin(), params(), populate_existing(), prefix_with(), reset_joinpoint(), scalar(), scalar_subquery(), select_from(), selectable, set_label_style(), slice(), statement, subquery(), suffix_with(), tuples(), union(), union_all(), update(), value(), values(), where(), whereclause, with_entities(), with_for_update(), with_hint(), with_labels(), with_parent(), with_session(), with_statement_hint(), with_transformation(), yield_per()

  Class signature

  class `sqlalchemy.orm.Query` (`sqlalchemy.sql.expression._SelectFromElements`, `sqlalchemy.sql.annotation.SupportsCloneAnnotations`, `sqlalchemy.sql.expression.HasPrefixes`, `sqlalchemy.sql.expression.HasSuffixes`, `sqlalchemy.sql.expression.HasHints`, `sqlalchemy.event.registry.EventTarget`, `sqlalchemy.log.Identified`, `sqlalchemy.sql.expression.Generative`, `sqlalchemy.sql.expression.Executable`, `typing.Generic`)

  method `sqlalchemy.orm.Query.`__init__(entities: _ColumnsClauseArgument[Any] | Sequence[_ColumnsClauseArgument[Any]], session: Session | None = None)

    Construct a `Query` directly.

    E.g.:

        q = Query([User, Address], session=some_session)

    The above is equivalent to:

        q = some_session.query(User, Address)

    Parameters:

      - entities – a sequence of entities and/or SQL expressions.

      - session – a `Session` with which the `Query` will be associated. Optional; a `Query` can be associated with a `Session` generatively via the `Query.with_session()` method as well.

    See also

    `Session.query()`

    `Query.with_session()`

  method `sqlalchemy.orm.Query.`add_column(column: _ColumnExpressionArgument[Any]) → Query[Any]

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

    Deprecated since version 1.4: `Query.add_column()` is deprecated and will be removed in a future release. Please use `Query.add_columns()`

  method `sqlalchemy.orm.Query.`add_columns(*column: _ColumnExpressionArgument[Any]) → Query[Any]

    Add one or more column expressions to the list of result columns to be returned.

    See also

    `Select.add_columns()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`add_entity(entity: _EntityType[Any], alias: Alias | Subquery | None = None) → Query[Any]

    add a mapped entity to the list of result columns to be returned.

    See also

    `Select.add_columns()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`all() → List[_T]

    Return the results represented by this `Query` as a list.

    This results in an execution of the underlying SQL statement.

    Warning

    The `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.

    > See also

    > My Query does not return the same number of objects as query.count() tells me - why?

    See also

    `Result.all()` - v2 comparable method.

    `Result.scalars()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`apply_labels() → Self

    Deprecated since version 2.0: The `Query.with_labels()` and `Query.apply_labels()` method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. Use set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL) instead. (Background on SQLAlchemy 2.0 at: SQLAlchemy 2.0 - Major Migration Guide)

  method `sqlalchemy.orm.Query.`as_scalar() → ScalarSelect[Any]

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

    Deprecated since version 1.4: The `Query.as_scalar()` method is deprecated and will be removed in a future release. Please refer to `Query.scalar_subquery()`.

  method `sqlalchemy.orm.Query.`autoflush(setting: bool) → Self

    Return a Query with a specific ‘autoflush’ setting.

    As of SQLAlchemy 1.4, the `Query.autoflush()` method is equivalent to using the `autoflush` execution option at the ORM level. See the section Autoflush for further background on this option.

  attribute `sqlalchemy.orm.Query.`column_descriptions

    Return metadata about the columns which would be returned by this `Query`.

    Format is a list of dictionaries:

        user_alias = aliased(User, name='user2')
        q = sess.query(User, User.id, user_alias)

        # this expression:
        q.column_descriptions

        # would return:
        [
            {
                'name':'User',
                'type':User,
                'aliased':False,
                'expr':User,
                'entity': User
            },
            {
                'name':'id',
                'type':Integer(),
                'aliased':False,
                'expr':User.id,
                'entity': User
            },
            {
                'name':'user2',
                'type':User,
                'aliased':True,
                'expr':user_alias,
                'entity': user_alias
            }
        ]

    See also

    This API is available using 2.0 style queries as well, documented at:

    - Inspecting entities and columns from ORM-enabled SELECT and DML statements

    - `Select.column_descriptions`

  method `sqlalchemy.orm.Query.`correlate(*fromclauses: Literal[None, False] | FromClauseRole | Type[Any] | Inspectable[_HasClauseElement[Any]] | _HasClauseElement[Any]) → Self

    Return a `Query` construct which will correlate the given FROM clauses to that of an enclosing `Query` or `select()`.

    The method here accepts mapped classes, `aliased()` constructs, and `Mapper` constructs as arguments, which are resolved into expression constructs, in addition to appropriate expression constructs.

    The correlation arguments are ultimately passed to `Select.correlate()` after coercion to expression constructs.

    The correlation arguments take effect in such cases as when `Query.from_self()` is used, or when a subquery as returned by `Query.subquery()` is embedded in another `select()` construct.

    See also

    `Select.correlate()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`count() → int

    Return a count of rows this the SQL formed by this `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 `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 `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.

    See also

    My Query does not return the same number of objects as query.count() tells me - why?

    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 `expression.func` expressions in conjunction with `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)))

    See also

    2.0 Migration - ORM Usage

  method `sqlalchemy.orm.Query.`cte(name: str | None = None, recursive: bool = False, nesting: bool = False) → CTE

    Return the full SELECT statement represented by this `Query` represented as a common table expression (CTE).

    Parameters and usage are the same as those of the `SelectBase.cte()` method; see that method for further details.

    Here is the PostgreSQL WITH RECURSIVE example. 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 `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)

    See also

    `Select.cte()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`delete(synchronize_session: SynchronizeSessionArgument = 'auto') → int

    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 ORM-Enabled INSERT, UPDATE, and DELETE statements for important caveats and warnings, including limitations when using bulk UPDATE and DELETE with mapper inheritance configurations.

    Parameters:

      synchronize_session – chooses the strategy to update the attributes on objects in the session. See the section ORM-Enabled INSERT, UPDATE, and DELETE statements for a discussion of these strategies.

    Returns:

      the count of rows matched as returned by the database’s “row count” feature.

    See also

    ORM-Enabled INSERT, UPDATE, and DELETE statements

  method `sqlalchemy.orm.Query.`distinct(*expr: _ColumnExpressionArgument[Any]) → Self

    Apply a `DISTINCT` to the query and return the newly resulting `Query`.

    Note

    The ORM-level `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 `Query`, however, so would not affect results. The columns are passed through when using the `Query.statement` accessor, however.

    Deprecated since version 2.0: This logic is deprecated and will be removed in SQLAlchemy 2.0. See Using DISTINCT with additional columns, but only select the entity for a description of this use case in 2.0.

    See also

    `Select.distinct()` - v2 equivalent method.

    Parameters:

      *expr –

      optional column expressions. When present, the PostgreSQL dialect will render a `DISTINCT ON (<expressions>)` construct.

      Deprecated since version 1.4: Using *expr in other dialects is deprecated and will raise `CompileError` in a future version.

  method `sqlalchemy.orm.Query.`enable_assertions(value: bool) → Self

    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.

  method `sqlalchemy.orm.Query.`enable_eagerloads(value: bool) → Self

    Control whether or not eager joins and subqueries are rendered.

    When set to False, the returned Query will not render eager joins regardless of `joinedload()`, `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 `Query.yield_per()`.

  method `sqlalchemy.orm.Query.`except_(*q: Query) → Self

    Produce an EXCEPT of this Query against one or more queries.

    Works the same way as `Query.union()`. See that method for usage examples.

    See also

    `Select.except_()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`except_all(*q: Query) → Self

    Produce an EXCEPT ALL of this Query against one or more queries.

    Works the same way as `Query.union()`. See that method for usage examples.

    See also

    `Select.except_all()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`execution_options(**kwargs: Any) → Self

    Set non-SQL options which take effect during execution.

    Options allowed here include all of those accepted by `Connection.execution_options()`, as well as a series of ORM specific options:

    `populate_existing=True` - equivalent to using `Query.populate_existing()`

    `autoflush=True|False` - equivalent to using `Query.autoflush()`

    `yield_per=<value>` - equivalent to using `Query.yield_per()`

    Note that the `stream_results` execution option is enabled automatically if the `Query.yield_per()` method or execution option is used.

    New in version 1.4: - added ORM options to `Query.execution_options()`

    The execution options may also be specified on a per execution basis when using 2.0 style queries via the `Session.execution_options` parameter.

    Warning

    The `Connection.execution_options.stream_results` parameter should not be used at the level of individual ORM statement executions, as the `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 `Session`, see Horizontal Sharding.

    See also

    Using Server Side Cursors (a.k.a. stream results)

    `Query.get_execution_options()`

    `Select.execution_options()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`exists() → Exists

    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 `literal()`:

        from sqlalchemy import literal

        session.query(literal(True)).filter(q.exists()).scalar()

    See also

    `Select.exists()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`filter(*criterion: _ColumnExpressionArgument[bool]) → Self

    Apply the given filtering criterion to a copy of this `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 `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 `text()` construct.

    See also

    `Query.filter_by()` - filter on keyword expressions.

    `Select.where()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`filter_by(**kwargs: Any) → Self

    Apply the given filtering criterion to a copy of this `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 `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 `Query.join()`.

    See also

    `Query.filter()` - filter on SQL expressions.

    `Select.filter_by()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`first() → _T | None

    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 `Query.first()` results in an execution of the underlying query.

    See also

    `Query.one()`

    `Query.one_or_none()`

    `Result.first()` - v2 comparable method.

    `Result.scalars()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`from_statement(statement: ExecutableReturnsRows) → Self

    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 `text()` or `select()` construct, and should return the set of columns appropriate to the entity class represented by this `Query`.

    See also

    `Select.from_statement()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`get(ident: _PKIdentityArgument) → Any | None

    Return an instance based on the given primary key identifier, or `None` if not found.

    Deprecated since version 2.0: The `Query.get()` method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. The method is now available as `Session.get()` (Background on SQLAlchemy 2.0 at: SQLAlchemy 2.0 - Major Migration Guide)

    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})

    `Query.get()` is special in that it provides direct access to the identity map of the owning `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.

    `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, `ObjectDeletedError` is raised.

    `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 `Query` must be constructed in this way, i.e. against a single mapped entity, with no additional filtering criterion. Loading options via `Query.options()` may be applied however, and will be used if the object is not yet locally present.

    Parameters:

      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 `Table` object’s primary key columns, or if the `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})

      New in version 1.3: the `Query.get()` method now optionally accepts a dictionary of attribute names to values in order to indicate a primary key identifier.

    Returns:

      The object instance, or `None`.

  method `sqlalchemy.orm.Query.`get_children(*, omit_attrs: Tuple[str, ...] = (), **kw: Any) → Iterable[HasTraverseInternals]

    inherited from the `HasTraverseInternals.get_children()` method of `HasTraverseInternals`

    Return immediate child `HasTraverseInternals` elements of this `HasTraverseInternals`.

    This is used for visit traversal.

    **kw may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  method `sqlalchemy.orm.Query.`get_execution_options() → _ImmutableExecuteOptions

    Get the non-SQL options which will take effect during execution.

    New in version 1.3.

    See also

    `Query.execution_options()`

    `Select.get_execution_options()` - v2 comparable method.

  attribute `sqlalchemy.orm.Query.`get_label_style

    Retrieve the current label style.

    New in version 1.4.

    See also

    `Select.get_label_style()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`group_by(_Query__first: Literal[None, False, _NoArg.NO_ARG] | _ColumnExpressionOrStrLabelArgument[Any] = _NoArg.NO_ARG, *clauses: _ColumnExpressionOrStrLabelArgument[Any]) → Self

    Apply one or more GROUP BY criterion to the query and return the newly resulting `Query`.

    All existing GROUP BY settings can be suppressed by passing `None` - this will suppress any GROUP BY configured on mappers as well.

    See also

    These sections describe GROUP BY in terms of 2.0 style invocation but apply to `Query` as well:

    Aggregate functions with GROUP BY / HAVING - in the SQLAlchemy Unified Tutorial

    Ordering or Grouping by a Label - in the SQLAlchemy Unified Tutorial

    `Select.group_by()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`having(*having: _ColumnExpressionArgument[bool]) → Self

    Apply a HAVING criterion to the query and return the newly resulting `Query`.

    `Query.having()` is used in conjunction with `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)

    See also

    `Select.having()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`instances(result_proxy: CursorResult[Any], context: QueryContext | None = None) → Any

    Return an ORM result given a `CursorResult` and `QueryContext`.

    Deprecated since version 2.0: The `Query.instances()` method is deprecated and will be removed in a future release. Use the Select.from_statement() method or aliased() construct in conjunction with Session.execute() instead.

  method `sqlalchemy.orm.Query.`intersect(*q: Query) → Self

    Produce an INTERSECT of this Query against one or more queries.

    Works the same way as `Query.union()`. See that method for usage examples.

    See also

    `Select.intersect()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`intersect_all(*q: Query) → Self

    Produce an INTERSECT ALL of this Query against one or more queries.

    Works the same way as `Query.union()`. See that method for usage examples.

    See also

    `Select.intersect_all()` - v2 equivalent method.

  attribute `sqlalchemy.orm.Query.`is_single_entity

    Indicates if this `Query` returns tuples or single entities.

    Returns True if this query returns a single entity for each instance in its result list, and False if this query returns a tuple of entities for each result.

    New in version 1.3.11.

    See also

    `Query.only_return_tuples()`

  method `sqlalchemy.orm.Query.`join(target: _JoinTargetArgument, onclause: _OnClauseArgument | None = None, *, isouter: bool = False, full: bool = False) → Self

    Create a SQL JOIN against this `Query` object’s criterion and apply generatively, returning the newly resulting `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 `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 `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 `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 `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 `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 `Query.join()` allows any mapped entity or core selectable construct as a target. In this usage, `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, `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 `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 `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 `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')
        )

    New in version 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 `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 `Query` is not in line with what we want to join from, the `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

    See also

    `Select.join()` - v2 equivalent method.

    Parameters:

      - *props – Incoming arguments for `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.

      - isouter=False – If True, the join used will be a left outer join, just as if the `Query.outerjoin()` method were called.

      - full=False – render FULL OUTER JOIN; implies `isouter`.

  method `sqlalchemy.orm.Query.`label(name: str | None) → Label[Any]

    Return the full SELECT statement represented by this `Query`, converted to a scalar subquery with a label of the given name.

    See also

    `Select.label()` - v2 comparable method.

  attribute `sqlalchemy.orm.Query.`lazy_loaded_from

    An `InstanceState` that is using this `Query` for a lazy load operation.

    Deprecated since version 1.4: This attribute should be viewed via the `ORMExecuteState.lazy_loaded_from` attribute, within the context of the `SessionEvents.do_orm_execute()` event.

    See also

    `ORMExecuteState.lazy_loaded_from`

  method `sqlalchemy.orm.Query.`limit(limit: _LimitOffsetType) → Self

    Apply a `LIMIT` to the query and return the newly resulting `Query`.

    See also

    `Select.limit()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`merge_result(iterator: FrozenResult[Any] | Iterable[Sequence[Any]] | Iterable[object], load: bool = True) → FrozenResult[Any] | Iterable[Any]

    Merge a result into this `Query` object’s Session.

    Deprecated since version 2.0: The `Query.merge_result()` method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. The method is superseded by the `merge_frozen_result()` function. (Background on SQLAlchemy 2.0 at: SQLAlchemy 2.0 - Major Migration Guide)

    Given an iterator returned by a `Query` of the same structure as this one, return an identical iterator of results, with all mapped instances merged into the session using `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 `Session.merge()` explicitly for each value.

    The structure of the results is determined based on the column list of this `Query` - if these do not correspond, unchecked errors will occur.

    The ‘load’ argument is the same as that of `Session.merge()`.

    For an example of how `Query.merge_result()` is used, see the source code for the example Dogpile Caching, where `Query.merge_result()` is used to efficiently restore state from a cache back into a target `Session`.

  method `sqlalchemy.orm.Query.`offset(offset: _LimitOffsetType) → Self

    Apply an `OFFSET` to the query and return the newly resulting `Query`.

    See also

    `Select.offset()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`one() → _T

    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 `one()` results in an execution of the underlying query.

    See also

    `Query.first()`

    `Query.one_or_none()`

    `Result.one()` - v2 comparable method.

    `Result.scalar_one()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`one_or_none() → _T | None

    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 `Query.one_or_none()` results in an execution of the underlying query.

    See also

    `Query.first()`

    `Query.one()`

    `Result.one_or_none()` - v2 comparable method.

    `Result.scalar_one_or_none()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`only_return_tuples(value: bool) → Query

    When set to True, the query results will always be a `Row` object.

    This can change a query that normally returns a single entity as a scalar to return a `Row` result in all cases.

    See also

    `Query.tuples()` - returns tuples, but also at the typing level will type results as `Tuple`.

    `Query.is_single_entity()`

    `Result.tuples()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`options(*args: ExecutableOption) → Self

    Return a new `Query` object, applying the given list of mapper options.

    Most supplied options regard changing how column- and relationship-mapped attributes are loaded.

    See also

    Column Loading Options

    Relationship Loading with Loader Options

  method `sqlalchemy.orm.Query.`order_by(_Query__first: Literal[None, False, _NoArg.NO_ARG] | _ColumnExpressionOrStrLabelArgument[Any] = _NoArg.NO_ARG, *clauses: _ColumnExpressionOrStrLabelArgument[Any]) → Self

    Apply one or more ORDER BY criteria to the query and return the newly resulting `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 `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)

    See also

    These sections describe ORDER BY in terms of 2.0 style invocation but apply to `Query` as well:

    ORDER BY - in the SQLAlchemy Unified Tutorial

    Ordering or Grouping by a Label - in the SQLAlchemy Unified Tutorial

    `Select.order_by()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`outerjoin(target: _JoinTargetArgument, onclause: _OnClauseArgument | None = None, *, full: bool = False) → Self

    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.

    See also

    `Select.outerjoin()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`params(_Query__params: Dict[str, Any] | None = None, **kw: Any) → Self

    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.

  method `sqlalchemy.orm.Query.`populate_existing() → Self

    Return a `Query` that will expire and refresh all instances as they are loaded, or reused from the current `Session`.

    As of SQLAlchemy 1.4, the `Query.populate_existing()` method is equivalent to using the `populate_existing` execution option at the ORM level. See the section Populate Existing for further background on this option.

  method `sqlalchemy.orm.Query.`prefix_with(*prefixes: _TextCoercedExpressionArgument[Any], dialect: str = '*') → Self

    inherited from the `HasPrefixes.prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

        # MySQL 5.7 optimizer hints
        stmt = select(table).prefix_with(
            "/*+ BKA(t1) */", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `HasPrefixes.prefix_with()`.

    Parameters:

      - *prefixes – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword.

      - dialect – optional string dialect name which will limit rendering of this prefix to only that dialect.

  method `sqlalchemy.orm.Query.`reset_joinpoint() → Self

    Return a new `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 `Query.join()` method. See the example in `Query.join()` for how this is used.

  method `sqlalchemy.orm.Query.`scalar() → Any

    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.

    See also

    `Result.scalar()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`scalar_subquery() → ScalarSelect[Any]

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

    Analogous to `SelectBase.scalar_subquery()`.

    Changed in version 1.4: The `Query.scalar_subquery()` method replaces the `Query.as_scalar()` method.

    See also

    `Select.scalar_subquery()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`select_from(*from_obj: FromClauseRole | Type[Any] | Inspectable[_HasClauseElement[Any]] | _HasClauseElement[Any]) → Self

    Set the FROM clause of this `Query` explicitly.

    `Query.select_from()` is often used in conjunction with `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 `Query.join()`, when no joinpoint is otherwise established - usually, the default “join point” is the leftmost entity in the `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

    Parameters:

      *from_obj – collection of one or more entities to apply to the FROM clause. Entities can be mapped classes, `AliasedClass` objects, `Mapper` objects as well as core `FromClause` elements like subqueries.

    See also

    `Query.join()`

    `Query.select_entity_from()`

    `Select.select_from()` - v2 equivalent method.

  attribute `sqlalchemy.orm.Query.`selectable

    Return the `Select` object emitted by this `Query`.

    Used for `inspect()` compatibility, this is equivalent to:

        query.enable_eagerloads(False).with_labels().statement

  method `sqlalchemy.orm.Query.`set_label_style(style: SelectLabelStyle) → Self

    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 `Query.set_label_style()` method only applies the output of `Query.statement`, and not to any of the result-row invoking systems of `Query` itself, e.g. `Query.first()`, `Query.all()`, etc. To execute a query using `Query.set_label_style()`, invoke the `Query.statement` using `Session.execute()`:

        result = session.execute(
            query
            .set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL)
            .statement
        )

    New in version 1.4.

    See also

    `Select.set_label_style()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`slice(start: int, stop: int) → Self

    Computes the “slice” of the `Query` represented by the given indices and returns the resulting `Query`.

    The start and stop indices behave like the argument to Python’s built-in `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

        SELECT users.id AS users_id,
               users.name AS users_name
        FROM users ORDER BY users.id
        LIMIT ? OFFSET ?
        (2, 1)

    See also

    `Query.limit()`

    `Query.offset()`

    `Select.slice()` - v2 equivalent method.

  attribute `sqlalchemy.orm.Query.`statement

    The full SELECT statement represented by this Query.

    The statement by default will not have disambiguating labels applied to the construct unless with_labels(True) is called first.

  method `sqlalchemy.orm.Query.`subquery(name: str | None = None, with_labels: bool = False, reduce_columns: bool = False) → Subquery

    Return the full SELECT statement represented by this `Query`, embedded within an `Alias`.

    Eager JOIN generation within the query is disabled.

    See also

    `Select.subquery()` - v2 comparable method.

    Parameters:

      - name – string name to be assigned as the alias; this is passed through to `FromClause.alias()`. If `None`, a name will be deterministically generated at compile time.

      - with_labels – if True, `with_labels()` will be called on the `Query` first to apply table-qualified labels to all columns.

      - reduce_columns – if True, `Select.reduce_columns()` will be called on the resulting `select()` construct, to remove same-named columns where one also refers to the other via foreign key or WHERE clause equivalence.

  method `sqlalchemy.orm.Query.`suffix_with(*suffixes: _TextCoercedExpressionArgument[Any], dialect: str = '*') → Self

    inherited from the `HasSuffixes.suffix_with()` method of `HasSuffixes`

    Add one or more expressions following the statement as a whole.

    This is used to support backend-specific suffix keywords on certain constructs.

    E.g.:

        stmt = select(col1, col2).cte().suffix_with(
            "cycle empno set y_cycle to 1 default 0", dialect="oracle")

    Multiple suffixes can be specified by multiple calls to `HasSuffixes.suffix_with()`.

    Parameters:

      - *suffixes – textual or `ClauseElement` construct which will be rendered following the target clause.

      - dialect – Optional string dialect name which will limit rendering of this suffix to only that dialect.

  method `sqlalchemy.orm.Query.`tuples() → Query

    return a tuple-typed form of this `Query`.

    This method invokes the `Query.only_return_tuples()` method with a value of `True`, which by itself ensures that this `Query` will always return `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 `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 `Query` object is a typed query object already.

    New in version 2.0.

    See also

    `Result.tuples()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`union(*q: Query) → Self

    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 `Query` object will not render ORDER BY within its SELECT statement.

    See also

    `Select.union()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`union_all(*q: Query) → Self

    Produce a UNION ALL of this Query against one or more queries.

    Works the same way as `Query.union()`. See that method for usage examples.

    See also

    `Select.union_all()` - v2 equivalent method.

  method `sqlalchemy.orm.Query.`update(values: Dict[_DMLColumnArgument, Any], synchronize_session: SynchronizeSessionArgument = 'auto', update_args: Dict[Any, Any] | None = None) → int

    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 ORM-Enabled INSERT, UPDATE, and DELETE statements for important caveats and warnings, including limitations when using arbitrary UPDATE and DELETE with mapper inheritance configurations.

    Parameters:

      - values – a dictionary with attributes names, or alternatively mapped attributes or SQL expressions, as keys, and literal values or sql expressions as values. If parameter-ordered mode is desired, the values can be passed as a list of 2-tuples; this requires that the `update.preserve_parameter_order` flag is passed to the `Query.update.update_args` dictionary as well.

      - synchronize_session – chooses the strategy to update the attributes on objects in the session. See the section ORM-Enabled INSERT, UPDATE, and DELETE statements for a discussion of these strategies.

      - update_args – Optional dictionary, if present will be passed to the underlying `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 `update.preserve_parameter_order`.

    Returns:

      the count of rows matched as returned by the database’s “row count” feature.

    See also

    ORM-Enabled INSERT, UPDATE, and DELETE statements

  method `sqlalchemy.orm.Query.`value(column: _ColumnExpressionArgument[Any]) → Any

    Return a scalar result corresponding to the given column expression.

    Deprecated since version 1.4: `Query.value()` is deprecated and will be removed in a future release. Please use `Query.with_entities()` in combination with `Query.scalar()`

  method `sqlalchemy.orm.Query.`values(*columns: _ColumnsClauseArgument[Any]) → Iterable[Any]

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

    Deprecated since version 1.4: `Query.values()` is deprecated and will be removed in a future release. Please use `Query.with_entities()`

  method `sqlalchemy.orm.Query.`where(*criterion: _ColumnExpressionArgument[bool]) → Self

    A synonym for `Query.filter()`.

    New in version 1.4.

    See also

    `Select.where()` - v2 equivalent method.

  attribute `sqlalchemy.orm.Query.`whereclause

    A readonly attribute which returns the current WHERE criterion for this Query.

    This returned value is a SQL expression construct, or `None` if no criterion has been established.

    See also

    `Select.whereclause` - v2 equivalent property.

  method `sqlalchemy.orm.Query.`with_entities(*entities: _ColumnsClauseArgument[Any], **_Query__kw: Any) → Query[Any]

    Return a new `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)

    See also

    `Select.with_only_columns()` - v2 comparable method.

  method `sqlalchemy.orm.Query.`with_for_update(*, nowait: bool = False, read: bool = False, of: _ForUpdateOfArgument | None = None, skip_locked: bool = False, key_share: bool = False) → Self

    return a new `Query` with the specified options for the `FOR UPDATE` clause.

    The behavior of this method is identical to that of `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 `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 `Query.populate_existing()` method when using the `Query.with_for_update()` method. The purpose of `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 identity map.

    See also

    `GenerativeSelect.with_for_update()` - Core level method with full argument and behavioral description.

    `Query.populate_existing()` - overwrites attributes of objects already loaded in the identity map.

  method `sqlalchemy.orm.Query.`with_hint(selectable: _FromClauseArgument, text: str, dialect_name: str = '*') → Self

    inherited from the `HasHints.with_hint()` method of `HasHints`

    Add an indexing or other executional context hint for the given selectable to this `Select` or other selectable object.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the given `Table` or `Alias` passed as the `selectable` argument. The dialect implementation typically uses Python string substitution syntax with the token `%(name)s` to render the name of the table or alias. E.g. when using Oracle, the following:

        select(mytable).\
            with_hint(mytable, "index(%(name)s ix_mytable)")

    Would render SQL as:

        select /*+ index(mytable ix_mytable) */ ... from mytable

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add hints for both Oracle and Sybase simultaneously:

        select(mytable).\
            with_hint(mytable, "index(%(name)s ix_mytable)", 'oracle').\
            with_hint(mytable, "WITH INDEX ix_mytable", 'mssql')

    See also

    `Select.with_statement_hint()`

  method `sqlalchemy.orm.Query.`with_labels() → Self

    Deprecated since version 2.0: The `Query.with_labels()` and `Query.apply_labels()` method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. Use set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL) instead. (Background on SQLAlchemy 2.0 at: SQLAlchemy 2.0 - Major Migration Guide)

  method `sqlalchemy.orm.Query.`with_parent(instance: object, property: attributes.QueryableAttribute[Any] | None = None, from_entity: _ExternalEntityType[Any] | None = None) → Self

    Add filtering criterion that relates the given instance to a child object or collection, using its attribute state as well as an established `relationship()` configuration.

    Deprecated since version 2.0: The `Query.with_parent()` method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. Use the `with_parent()` standalone construct. (Background on SQLAlchemy 2.0 at: SQLAlchemy 2.0 - Major Migration Guide)

    The method uses the `with_parent()` function to generate the clause, the result of which is passed to `Query.filter()`.

    Parameters are the same as `with_parent()`, with the exception that the given property can be None, in which case a search is performed against this `Query` object’s target mapper.

    Parameters:

      - instance – An instance which has some `relationship()`.

      - property – Class bound attribute which indicates what relationship from the instance should be used to reconcile the parent/child relationship.

      - from_entity – Entity in which to consider as the left side. This defaults to the “zero” entity of the `Query` itself.

  method `sqlalchemy.orm.Query.`with_session(session: Session) → Self

    Return a `Query` that will use the given `Session`.

    While the `Query` object is normally instantiated using the `Session.query()` method, it is legal to build the `Query` directly without necessarily using a `Session`. Such a `Query` object, or any `Query` already associated with a different `Session`, can produce a new `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()

  method `sqlalchemy.orm.Query.`with_statement_hint(text: str, dialect_name: str = '*') → Self

    inherited from the `HasHints.with_statement_hint()` method of `HasHints`

    Add a statement hint to this `Select` or other selectable object.

    This method is similar to `Select.with_hint()` except that it does not require an individual table, and instead applies to the statement as a whole.

    Hints here are specific to the backend database and may include directives such as isolation levels, file directives, fetch directives, etc.

    See also

    `Select.with_hint()`

    `Select.prefix_with()` - generic SELECT prefixing which also can suit some database-specific HINT syntaxes such as MySQL optimizer hints

  method `sqlalchemy.orm.Query.`with_transformation(fn: Callable[[Query], Query]) → Query

    Return a new `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 `Query` objects.

  method `sqlalchemy.orm.Query.`yield_per(count: int) → Self

    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 `Query.yield_per()` method is equivalent to using the `yield_per` execution option at the ORM level. See the section Fetching Large Result Sets with Yield Per for further background on this option.

    See also

    Fetching Large Result Sets with Yield Per

## ORM-Specific Query Constructs

This section has moved to Additional ORM API Constructs.