Finds a single document matching the query.

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

This method has the following parameters:

Parameter Type Description
$filter array|object Optional. The filter criteria that specifies the documents to query.
$options array Optional. An array specifying the desired options.

The $options parameter supports the following options:

Option Type Description
projection array|object Optional. The projection specification to determine which fields to include in the returned documents. See Project Fields to Return from Query and Projection Operators in the MongoDB manual.
sort array|object Optional. The sort specification for the ordering of the results.
skip integer Optional. Number of documents to skip. Defaults to 0.
allowDiskUse boolean Optional. Enables writing to temporary files. When set to true, queries can write data to the _tmp sub-directory in the dbPath directory.
collation array|object

Optional. Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks. When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.

If the collation is unspecified but the collection has a default collation, the operation uses the collation specified for the collection. If no collation is specified for the collection or for the operation, MongoDB uses the simple binary comparison used in prior versions for string comparisons.

comment mixed

Optional. Enables users to specify an arbitrary comment to help trace the operation through the database profiler, currentOp output, and logs.

The comment can be any valid BSON type for server versions 4.4 and above. Earlier server versions only support string values.

hint string|array|object

Optional. The index to use. Specify either the index name as a string or the index key pattern as a document. If specified, then the query system will only consider plans using the hinted index.

New in version 1.2.

maxTimeMS integer Optional. The cumulative time limit in milliseconds for processing operations on the cursor. MongoDB aborts the operation at the earliest following interrupt point.
readConcern MongoDB\Driver\ReadConcern

Optional. Read concern to use for the operation. Defaults to the collection’s read concern.

It is not possible to specify a read concern for individual operations as part of a transaction. Instead, set the readConcern option when starting the transaction with startTransaction.

readPreference MongoDB\Driver\ReadPreference Optional. Read preference to use for the operation. Defaults to the collection’s read preference.
session MongoDB\Driver\Session

Optional. Client session to associate with the operation.

New in version 1.3.

typeMap array

Optional. The type map to apply to cursors, which determines how BSON documents are converted to PHP values. Defaults to the collection’s type map.

This will be used for the returned result document.

max array|object

Optional. The exclusive upper bound for a specific index.

New in version 1.2.

maxScan integer

Optional. Maximum number of documents or index keys to scan when executing the query.

Deprecated since version 1.4.

New in version 1.2.

min array|object

Optional. The inclusive lower bound for a specific index.

New in version 1.2.

returnKey boolean

Optional. If true, returns only the index keys in the resulting documents.

New in version 1.2.

showRecordId boolean

Optional. Determines whether to return the record identifier for each document. If true, adds a field $recordId to the returned documents.

New in version 1.2.

modifiers array|object Optional. Meta operators that modify the output or behavior of a query. Use of these operators is deprecated in favor of named options.
let array|object

Optional. Map of parameter names and values. Values must be constant or closed expressions that do not reference document fields. Parameters can then be accessed as variables in an aggregate expression context (e.g. $$var).

This is not supported for server versions prior to 5.0 and will result in an exception at execution time if used.

New in version 1.13.

Return Values

An array or object for the first document that matched the query, or null if no document matched the query. The return type will depend on the typeMap option.


MongoDB\Exception\UnsupportedException if options are used and not supported by the selected server (e.g. collation, readConcern, writeConcern).

MongoDB\Exception\InvalidArgumentException for errors related to the parsing of parameters or options.

MongoDB\Driver\Exception\RuntimeException for other errors at the driver level (e.g. connection errors).


When evaluating query criteria, MongoDB compares types and values according to its own comparison rules for BSON types, which differs from PHP’s comparison and type juggling rules. When matching a special BSON type the query criteria should use the respective BSON class in the driver (e.g. use MongoDB\BSON\ObjectId to match an ObjectId).


Matching BSON Types in Query Criteria

In the following example, documents in the restaurants collection use an ObjectId 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 MongoDB\BSON\ObjectId class.


$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 projection to limit the fields that are returned.


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

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


The output would then resemble:

object(MongoDB\Model\BSONDocument)#10 (1) {
  array(4) {
    object(MongoDB\BSON\ObjectId)#8 (1) {
      string(24) "576023c6b02fa9281da3f983"
    string(9) "Manhattan"
    string(7) "Italian"
    string(23) "Isle Of Capri Resturant"

See Also