==============================
MongoDB\\Collection::findOne()
==============================

.. default-domain:: mongodb

.. contents:: On this page
   :local:
   :backlinks: none
   :depth: 1
   :class: singlecol

Definition
----------

.. phpmethod:: MongoDB\Collection::findOne()

   Finds a single document matching the query.

   .. code-block:: php

      function findOne(
          array|object $filter = [],
          array $options = []
      ): array|object|null

Parameters
----------

``$filter`` : array|object
  The filter criteria that specifies the documents to query.

``$options`` : array
  An array specifying the desired options.

  .. list-table::
     :header-rows: 1
     :widths: 20 20 80

     * - Name
       - Type
       - Description

     * - allowDiskUse
       - boolean
       - Enables writing to temporary files. When set to ``true``, queries can
         write data to the ``_tmp`` sub-directory in the ``dbPath`` directory.

     * - allowPartialResults
       - boolean
       - For queries against a sharded collection, returns partial results from
         the :program:`mongos` if some shards are unavailable instead of
         throwing an error.

     * - codec
       - MongoDB\\Codec\\DocumentCodec
       - .. include:: /includes/extracts/collection-option-codec.rst

         .. versionadded:: 1.17

     * - collation
       - array|object
       - .. include:: /includes/extracts/collection-option-collation.rst

     * - comment
       - mixed
       - .. include:: /includes/extracts/common-option-comment.rst

         .. include:: /includes/extracts/common-option-comment-string-before-4.4.rst

     * - hint
       - string|array|object
       - .. include:: /includes/extracts/common-option-hint.rst

         .. versionadded:: 1.2

     * - let
       - array|object
       - .. include:: /includes/extracts/common-option-let.rst

         .. versionadded:: 1.13

     * - max
       - array|object
       - The exclusive upper bound for a specific index.

         .. versionadded:: 1.2

     * - maxScan
       - integer
       - Maximum number of documents or index keys to scan when executing the
         query.

         .. deprecated:: 1.4
         .. versionadded:: 1.2

     * - maxTimeMS
       - integer
       - .. include:: /includes/extracts/common-option-maxTimeMS.rst

     * - min
       - array|object
       - The inclusive lower bound for a specific index.

         .. versionadded:: 1.2

     * - modifiers
       - array|object
       - :manual:`Meta operators </reference/operator/query-modifier>` that
         modify the output or behavior of a query. Use of these operators is
         deprecated in favor of named options.

     * - oplogReplay
       - boolean
       - Internal use for replica sets. To use ``oplogReplay``, you must include
         the following condition in the filter:

         .. code-block:: javascript

            { ts: { $gte: <timestamp> } }

         The :php:`MongoDB\BSON\Timestamp <class.mongodb-bson-timestamp>`
         class reference describes how to represent MongoDB's BSON timestamp
         type with PHP.

         .. deprecated:: 1.7

     * - projection
       - array|object
       - The :ref:`projection specification <projections>` to determine which
         fields to include in the returned documents. See
         :manual:`Project Fields to Return from Query </tutorial/project-fields-from-query-results>`
         and :manual:`Projection Operators </reference/operator/projection>` in
         the MongoDB manual.

     * - readConcern
       - :php:`MongoDB\Driver\ReadConcern <class.mongodb-driver-readconcern>`
       - .. include:: /includes/extracts/collection-option-readConcern.rst

         .. include:: /includes/extracts/common-option-readConcern-transaction.rst

     * - readPreference
       - :php:`MongoDB\Driver\ReadPreference <class.mongodb-driver-readpreference>`
       - .. include:: /includes/extracts/collection-option-readPreference.rst

     * - returnKey
       - boolean
       - If true, returns only the index keys in the resulting documents.

         .. versionadded:: 1.2

     * - session
       - :php:`MongoDB\Driver\Session <class.mongodb-driver-session>`
       - .. include:: /includes/extracts/common-option-session.rst

         .. versionadded:: 1.3

     * - showRecordId
       - boolean
       - Determines whether to return the record identifier for each document.
         If true, adds a field ``$recordId`` to the returned documents.

         .. versionadded:: 1.2

     * - skip
       - integer
       - Number of documents to skip. Defaults to ``0``.

     * - sort
       - array|object
       - The sort specification for the ordering of the results.

     * - typeMap
       - array
       - .. include:: /includes/extracts/collection-option-typeMap.rst

         This will be used for the returned result document.

Return Values
-------------

An array or object for the :term:`first document <natural order>` that matched
the query, or ``null`` if no document matched the query. The return type will
depend on the ``typeMap`` option.

Errors/Exceptions
-----------------

.. include:: /includes/extracts/error-unsupportedexception.rst
.. include:: /includes/extracts/error-invalidargumentexception.rst
.. include:: /includes/extracts/error-driver-runtimeexception.rst

Behavior
--------

.. include:: /includes/extracts/note-bson-comparison.rst

Examples
--------

Matching BSON Types in Query Criteria
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In the following example, documents in the ``restaurants`` collection use an
:manual:`ObjectId </reference/object-id/>` for their identifier (the default)
and documents in the ``zips`` collection use a string. Since ObjectId is a
special BSON type, the query criteria for selecting a restaurant must use the
:php:`MongoDB\BSON\ObjectId <class.mongodb-bson-objectid>` class.

.. code-block:: php

   <?php

   $database = (new MongoDB\Client)->test;

   $zip = $database->zips->findOne(['_id' => '10036']);

   $restaurant = $database->restaurants->findOne([
       '_id' => new MongoDB\BSON\ObjectId('594d5ef280a846852a4b3f70'),
   ]);

Projecting Fields
~~~~~~~~~~~~~~~~~

The following example finds a restaurant based on the ``cuisine`` and
``borough`` fields and uses a :manual:`projection
</tutorial/project-fields-from-query-results>` to limit the fields that are
returned.

.. code-block:: php

   <?php

   $collection = (new MongoDB\Client)->test->restaurants;

   $restaurant = $collection->findOne(
       [
           'cuisine' => 'Italian',
           'borough' => 'Manhattan',
       ],
       [
           'projection' => [
               'name' => 1,
               'borough' => 1,
               'cuisine' => 1,
           ],
       ]
   );

   var_dump($restaurant);

The output would then resemble:

.. code-block:: none

   object(MongoDB\Model\BSONDocument)#10 (1) {
     ["storage":"ArrayObject":private]=>
     array(4) {
       ["_id"]=>
       object(MongoDB\BSON\ObjectId)#8 (1) {
         ["oid"]=>
         string(24) "576023c6b02fa9281da3f983"
       }
       ["borough"]=>
       string(9) "Manhattan"
       ["cuisine"]=>
       string(7) "Italian"
       ["name"]=>
       string(23) "Isle Of Capri Resturant"
     }
   }

See Also
--------

- :phpmethod:`MongoDB\Collection::find()`
- :manual:`find </reference/command/find>` command reference in the MongoDB
  manual
