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Query Documents

This page provides examples of query operations using the db.collection.find() method in the mongo shell. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using MongoDB Compass. The examples on this page use the inventory collection. Populate the inventory collection with the following documents:

This page provides examples of query operations using the pymongo.collection.Collection.find() method in the PyMongo Python driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the com.mongodb.client.MongoCollection.find method in the MongoDB Java Synchronous Driver.

Tip

The driver provides com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents. The examples on this page use these methods to create the filter documents.

The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the Collection.find() method in the MongoDB Node.js Driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the MongoDB\Collection::find() method in the MongoDB PHP Library. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the com.mongodb.reactivestreams.client.MongoCollection.find method in the MongoDB Java Reactive Streams Driver.

The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the MongoCollection.Find() method in the MongoDB C# Driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the MongoDB::Collection::find() method in the MongoDB Perl Driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the Mongo::Collection#find() method in the MongoDB Ruby Driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

This page provides examples of query operations using the collection.find() method in the MongoDB Scala Driver. The examples on this page use the inventory collection. To populate the inventory collection, run the following:

db.inventory.insertMany([
   { item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
   { item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "A" },
   { item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" },
   { item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" },
   { item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" }
]);

You can run the operation in the web shell below:

[
   { item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
   { item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "A" },
   { item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" },
   { item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" },
   { item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" }
]

For instructions on inserting documents in MongoDB Compass, see Insert Documents.

db.inventory.insert_many([
    {"item": "journal",
     "qty": 25,
     "size": {"h": 14, "w": 21, "uom": "cm"},
     "status": "A"},
    {"item": "notebook",
     "qty": 50,
     "size": {"h": 8.5, "w": 11, "uom": "in"},
     "status": "A"},
    {"item": "paper",
     "qty": 100,
     "size": {"h": 8.5, "w": 11, "uom": "in"},
     "status": "D"},
    {"item": "planner",
     "qty": 75, "size": {"h": 22.85, "w": 30, "uom": "cm"},
     "status": "D"},
    {"item": "postcard",
     "qty": 45,
     "size": {"h": 10, "w": 15.25, "uom": "cm"},
     "status": "A"}])
collection.insertMany(asList(
        Document.parse("{ item: 'journal', qty: 25, size: { h: 14, w: 21, uom: 'cm' }, status: 'A' }"),
        Document.parse("{ item: 'notebook', qty: 50, size: { h: 8.5, w: 11, uom: 'in' }, status: 'A' }"),
        Document.parse("{ item: 'paper', qty: 100, size: { h: 8.5, w: 11, uom: 'in' }, status: 'D' }"),
        Document.parse("{ item: 'planner', qty: 75, size: { h: 22.85, w: 30, uom: 'cm' }, status: 'D' }"),
        Document.parse("{ item: 'postcard', qty: 45, size: { h: 10, w: 15.25, uom: 'cm' }, status: 'A' }")
));
db.collection('inventory').insertMany([
  { item: "journal",
    qty: 25,
    size: { h: 14, w: 21, uom: "cm" },
    status: "A"},
  { item: "notebook",
    qty: 50,
    size: { h: 8.5, w: 11, uom: "in" },
    status: "A"},
  { item: "paper",
    qty: 100,
    size: { h: 8.5, w: 11, uom: "in" },
    status: "D"},
  { item: "planner",
    qty: 75, size: { h: 22.85, w: 30, uom: "cm" },
    status: "D"},
  { item: "postcard",
    qty: 45,
    size: { h: 10, w: 15.25, uom: "cm" },
    status: "A"}
])
.then(function(result) {
  // process result
})
$insertManyResult = $db->inventory->insertMany([
    [
        'item' => 'journal', 
        'qty' => 25,
        'size' => ['h' => 14, 'w' => 21, 'uom' => 'cm'],
        'status' => 'A',
    ],
    [
        'item' => 'notebook', 
        'qty' => 50,
        'size' => ['h' => 8.5, 'w' => 11, 'uom' => 'in'],
        'status' => 'A',
    ],
    [
        'item' => 'paper', 
        'qty' => 100,
        'size' => ['h' => 8.5, 'w' => 11, 'uom' => 'in'],
        'status' => 'D',
    ],
    [
        'item' => 'planner', 
        'qty' => 75,
        'size' => ['h' => 22.85, 'w' => 30, 'uom' => 'cm'],
        'status' => 'D',
    ],
    [
        'item' => 'postcard', 
        'qty' => 45,
        'size' => ['h' => 10, 'w' => 15.25, 'uom' => 'cm'],
        'status' => 'A',
    ],
]);
Publisher<Success> insertManyPublisher = collection.insertMany(asList(
        Document.parse("{ item: 'journal', qty: 25, size: { h: 14, w: 21, uom: 'cm' }, status: 'A' }"),
        Document.parse("{ item: 'notebook', qty: 50, size: { h: 8.5, w: 11, uom: 'in' }, status: 'A' }"),
        Document.parse("{ item: 'paper', qty: 100, size: { h: 8.5, w: 11, uom: 'in' }, status: 'D' }"),
        Document.parse("{ item: 'planner', qty: 75, size: { h: 22.85, w: 30, uom: 'cm' }, status: 'D' }"),
        Document.parse("{ item: 'postcard', qty: 45, size: { h: 10, w: 15.25, uom: 'cm' }, status: 'A' }")
));
var documents = new BsonDocument[]
{
    new BsonDocument
    {
        { "item", "journal" },
        { "qty", 25 },
        { "size", new BsonDocument { { "h", 14 }, { "w", 21 }, {  "uom", "cm"} } },
        { "status", "A" }
    },
    new BsonDocument
    {
        { "item", "notebook" },
        { "qty", 50 },
        { "size", new BsonDocument { { "h",  8.5 }, { "w", 11 }, {  "uom", "in"} } },
        { "status", "A" }
    },
    new BsonDocument
    {
        { "item", "paper" },
        { "qty", 100 },
        { "size", new BsonDocument { { "h",  8.5 }, { "w", 11 }, {  "uom", "in"} } },
        { "status", "D" }
    },
    new BsonDocument
    {
        { "item", "planner" },
        { "qty", 75 },
        { "size", new BsonDocument { { "h", 22.85 }, { "w", 30  }, {  "uom", "cm"} } },
        { "status", "D" }
    },
    new BsonDocument
    {
        { "item", "postcard" },
        { "qty", 45 },
        { "size", new BsonDocument { { "h", 10 }, { "w", 15.25 }, {  "uom", "cm"} } },
        { "status", "A" }
    },
};
collection.InsertMany(documents);
$db->coll("inventory")->insert_many(
    [
        {
            item   => "journal",
            qty    => 25,
            size   => { h => 14, w => 21, uom => "cm" },
            status => "A"
        },
        {
            item   => "notebook",
            qty    => 50,
            size   => { h => 8.5, w => 11, uom => "in" },
            status => "A"
        },
        {
            item   => "paper",
            qty    => 100,
            size   => { h => 8.5, w => 11, uom => "in" },
            status => "D"
        },
        {
            item   => "planner",
            qty    => 75,
            size   => { h => 22.85, w => 30, uom => "cm" },
            status => "D"
        },
        {
            item   => "postcard",
            qty    => 45,
            size   => { h => 10, w => 15.25, uom => "cm" },
            status => "A"
        }
    ]
);
client[:inventory].insert_many([{ item: 'journal',
                                  qty: 25,
                                  size: { h: 14, w: 21, uom: 'cm' },
                                  status: 'A' },
                                { item: 'notebook',
                                  qty: 50,
                                  size: { h: 8.5, w: 11, uom: 'in' },
                                  status: 'A' },
                                { item: 'paper',
                                  qty: 100,
                                  size: { h: 8.5, w: 11, uom: 'in' },
                                  status: 'D' },
                                { item: 'planner',
                                  qty: 75,
                                  size: { h: 22.85, w: 30, uom: 'cm' },
                                  status: 'D' },
                                { item: 'postcard',
                                  qty: 45,
                                  size: { h: 10, w: 15.25, uom: 'cm' },
                                  status: 'A' }
                               ])
collection.insertMany(Seq(
  Document("""{ item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" }"""),
  Document("""{ item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "A" }"""),
  Document("""{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" }"""),
  Document("""{ item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" }"""),
  Document("""{ item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" }""")
)).execute()

Select All Documents in a Collection

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the query bar. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

To select all documents in the collection, pass an empty document as the query filter parameter to the find method. The query filter parameter determines the select criteria:

db.inventory.find( {} )
../../_images/compass-select-all.png
cursor = db.inventory.find({})
FindIterable<Document> findIterable = collection.find(new Document());
var cursor = db.collection('inventory').find({});
$cursor = $db->inventory->find([]);
FindPublisher<Document> findPublisher = collection.find(new Document());
var filter = Builders<BsonDocument>.Filter.Empty;
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find( {} );
client[:inventory].find({})
var findObservable = collection.find(Document())

This operation corresponds to the following SQL statement:

SELECT * FROM inventory

For more information on the syntax of the method, see find().

For more information on the MongoDB Compass query bar, see Query Bar.

For more information on the syntax of the method, see find().

For more information on the syntax of the method, see com.mongodb.client.MongoCollection.find.

For more information on the syntax of the method, see find().

For more information on the syntax of the method, see find().

For more information on the syntax of the method, see com.mongodb.reactivestreams.client.MongoCollection.find.

For more information on the syntax of the method, see Find().

For more information on the syntax of the method, see find().

For more information on the syntax of the method, see find().

For more information on the syntax of the method, see collection.find().

Specify Equality Condition

To specify equality conditions, use <field>:<value> expressions in the query filter document:

{ <field1>: <value1>, ... }

To specify equality conditions, use <field>:<value> expressions in the query filter document:

{ <field1>: <value1>, ... }

To specify equality conditions, use <field>:<value> expressions in the query filter document:

{ <field1>: <value1>, ... }

To specify equality conditions, use the com.mongodb.client.model.Filters.eq_ method to create the query filter document:

and(eq( <field1>, <value1>), eq( <field2>, <value2>) ...)

To specify equality conditions, use <field>:<value> expressions in the query filter document:

{ <field1>: <value1>, ... }

To specify equality conditions, use <field> => <value> expressions in the query filter document:

[ <field1> => <value1>, ... ]

To specify equality conditions, use the com.mongodb.client.model.Filters.eq method to create the query filter document:

and(eq( <field1>, <value1>), eq( <field2>, <value2>) ...)

To specify equality conditions, construct a filter using the Eq method:

Builders<BsonDocument>.Filter.Eq(<field>, <value>);

To specify equality conditions, use <field> => <value> expressions in the query filter document:

{ <field1> => <value1>, ... }

To specify equality conditions, use <field> => <value> expressions in the query filter document:

{ <field1> => <value1>, ... }

To specify equality conditions, use the com.mongodb.client.model.Filters.eq_ method to create the query filter document:

and(equal(<field1>, <value1>), equal(<field2>, <value2>) ...)

The following example selects from the inventory collection all documents where the status equals "D":

db.inventory.find( { status: "D" } )

Copy the following filter into the Compass query bar and click Find:

{ status: "D" }
../../_images/compass-find-filter-inventory.png
cursor = db.inventory.find({"status": "D"})
findIterable = collection.find(eq("status", "D"));
var cursor = db.collection('inventory').find({ status: "D" });
$cursor = $db->inventory->find(['status' => 'D']);
findPublisher = collection.find(eq("status", "D"));
var filter = Builders<BsonDocument>.Filter.Eq("status", "D");
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find( { status => "D" } );
client[:inventory].find(status: 'D')
findObservable = collection.find(equal("status", "D"))

This operation corresponds to the following SQL statement:

SELECT * FROM inventory WHERE status = "D"

Note

The MongoDB Compass query bar autocompletes the current query based on the keys in your collection’s documents, including keys in embedded sub-documents.

Specify Conditions Using Query Operators

A query filter document can use the query operators to specify conditions in the following form:

{ <field1>: { <operator1>: <value1> }, ... }

A query filter document can use the query operators to specify conditions in the following form:

{ <field1>: { <operator1>: <value1> }, ... }

A query filter document can use the query operators to specify conditions in the following form:

{ <field1>: { <operator1>: <value1> }, ... }

In addition to the equality condition, MongoDB provides various query operators to specify filter conditions. Use the com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents. For example:

and(gte(<field1>, <value1>), lt(<field2>, <value2>), eq(<field3>, <value3>))

A query filter document can use the query operators to specify conditions in the following form:

{ <field1>: { <operator1>: <value1> }, ... }

A query filter document can use the query operators to specify conditions in the following form:

[ <field1> => [ <operator1> => <value1> ], ... ]

In addition to the equality condition, MongoDB provides various query operators to specify filter conditions. Use the com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents. For example:

and(gte(<field1>, <value1>), lt(<field2>, <value2>), eq(<field3>, <value3>))

In addition to the equality filter, MongoDB provides various query operators to specify filter conditions. Use the FilterDefinitionBuilder methods to create a filter document. For example:

var builder = Builders<BsonDocument>.Filter;
builder.And(builder.Eq(<field1>, <value1>), builder.Lt(<field2>, <value2>));

A query filter document can use the query operators to specify conditions in the following form:

{ <field1> => { <operator1> => <value1> }, ... }

A query filter document can use the query operators to specify conditions in the following form:

{ <field1> => { <operator1> => <value1> }, ... }

In addition to the equality condition, MongoDB provides various query operators to specify filter conditions. Use the com.mongodb.client.model.Filters_ helper methods to facilitate the creation of filter documents. For example:

and(gte(<field1>, <value1>), lt(<field2>, <value2>), equal(<field3>, <value3>))

The following example retrieves all documents from the inventory collection where status equals either "A" or "D":

db.inventory.find( { status: { $in: [ "A", "D" ] } } )

Copy the following filter into the Compass query bar and click Find:

{ status: { $in: [ "A", "D" ] } }
../../_images/compass-find-filter-query-op.png
cursor = db.inventory.find({"status": {"$in": ["A", "D"]}})
findIterable = collection.find(in("status", "A", "D"));
var cursor = db.collection('inventory').find({ 
  status: { $in: ["A", "D"] }
});
$cursor = $db->inventory->find(['status' => ['$in' => ['A', 'D']]]);
findPublisher = collection.find(in("status", "A", "D"));
var filter = Builders<BsonDocument>.Filter.In("status", new[] { "A", "D" });
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find( { status => { '$in' => [ "A", "D" ] } } );
client[:inventory].find(status: { '$in' => [ 'A', 'D' ]})
findObservable = collection.find(in("status", "A", "D"))

Note

Although you can express this query using the $or operator, use the $in operator rather than the $or operator when performing equality checks on the same field.

The operation corresponds to the following SQL statement:

SELECT * FROM inventory WHERE status in ("A", "D")

Refer to the Query and Projection Operators document for the complete list of MongoDB query operators.

Specify AND Conditions

A compound query can specify conditions for more than one field in the collection’s documents. Implicitly, a logical AND conjunction connects the clauses of a compound query so that the query selects the documents in the collection that match all the conditions.

The following example retrieves all documents in the inventory collection where the status equals "A" and qty is less than ($lt) 30:

db.inventory.find( { status: "A", qty: { $lt: 30 } } )

Copy the following filter into the Compass query bar and click Find:

{ status: "A", qty: { $lt: 30 } }
../../_images/compass-find-filter-and.png
cursor = db.inventory.find({"status": "A", "qty": {"$lt": 30}})
findIterable = collection.find(and(eq("status", "A"), lt("qty", 30)));
var cursor = db.collection('inventory').find({ 
  status: "A", 
  qty: { $lt: 30 }
});
$cursor = $db->inventory->find([
    'status' => 'A',
    'qty' => ['$lt' => 30],
]);
findPublisher = collection.find(and(eq("status", "A"), lt("qty", 30)));
var builder = Builders<BsonDocument>.Filter;
var filter = builder.And(builder.Eq("status", "A"), builder.Lt("qty", 30));
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find( { status => "A", qty => { '$lt' => 30 } } );
client[:inventory].find(status: 'A', qty: { '$lt' => 30 })
findObservable = collection.find(and(equal("status", "A"), lt("qty", 30)))

The operation corresponds to the following SQL statement:

SELECT * FROM inventory WHERE status = "A" AND qty < 30

See comparison operators for other MongoDB comparison operators.

Specify OR Conditions

Using the $or operator, you can specify a compound query that joins each clause with a logical OR conjunction so that the query selects the documents in the collection that match at least one condition.

The following example retrieves all documents in the collection where the status equals "A" or qty is less than ($lt) 30:

db.inventory.find( { $or: [ { status: "A" }, { qty: { $lt: 30 } } ] } )

Copy the following filter into the Compass query bar and click Find:

{ $or: [ { status: "A" }, { qty: { $lt: 30 } } ] }
../../_images/compass-find-filter-or.png
cursor = db.inventory.find(
    {"$or": [{"status": "A"}, {"qty": {"$lt": 30}}]})
findIterable = collection.find(or(eq("status", "A"), lt("qty", 30)));
var cursor = db.collection('inventory').find({ 
  $or: [ {status: "A" }, { qty: { $lt: 30 } } ]
});
$cursor = $db->inventory->find([
    '$or' => [
        ['status' => 'A'],
        ['qty' => ['$lt' => 30]],
    ],
]);
findPublisher = collection.find(or(eq("status", "A"), lt("qty", 30)));
var builder = Builders<BsonDocument>.Filter;
var filter = builder.Or(builder.Eq("status", "A"), builder.Lt("qty", 30));
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find(
    { '$or' => [ { status => "A" }, { qty => { '$lt' => 30 } } ] }
);
client[:inventory].find('$or' => [{ status: 'A' },
                                  { qty: { '$lt' => 30 } }
                                 ])
findObservable = collection.find(or(equal("status", "A"), lt("qty", 30)))

The operation corresponds to the following SQL statement:

SELECT * FROM inventory WHERE status = "A" OR qty < 30

Note

Queries which use comparison operators are subject to Type Bracketing.

Specify AND as well as OR Conditions

In the following example, the compound query document selects all documents in the collection where the status equals "A" and either qty is less than ($lt) 30 or item starts with the character p:

db.inventory.find( {
     status: "A",
     $or: [ { qty: { $lt: 30 } }, { item: /^p/ } ]
} )

Copy the following filter into the Compass query bar and click Find:

{ status: "A", $or: [ { qty: { $lt: 30 } }, { item: /^p/ } ] }
../../_images/compass-find-filter-and-or.png
cursor = db.inventory.find({
    "status": "A",
    "$or": [{"qty": {"$lt": 30}}, {"item": {"$regex": "^p"}}]})
findIterable = collection.find(
        and(eq("status", "A"),
                or(lt("qty", 30), regex("item", "^p")))
);
var cursor = db.collection('inventory').find({ 
  status: "A",
  $or: [ { qty: { $lt: 30 } }, { item: { $regex: "^p" } } ]
});
$cursor = $db->inventory->find([
    'status' => 'A',
    '$or' => [
        ['qty' => ['$lt' => 30]],
        // Alternatively: ['item' => new \MongoDB\BSON\Regex('^p')]
        ['item' => ['$regex' => '^p']],
    ],
]);
findPublisher = collection.find(
        and(eq("status", "A"),
                or(lt("qty", 30), regex("item", "^p")))
);
var builder = Builders<BsonDocument>.Filter;
var filter = builder.And(
    builder.Eq("status", "A"),
    builder.Or(builder.Lt("qty", 30), builder.Regex("item", new BsonRegularExpression("^p"))));
var result = collection.Find(filter).ToList();
$cursor = $db->coll("inventory")->find(
    {
        status => "A",
        '$or'  => [ { qty => { '$lt' => 30 } }, { item => { '$regex' => "^p" } } ]
    }
);
client[:inventory].find(status: 'A',
                        '$or' => [{ qty: { '$lt' => 30 } },
                                  { item: { '$regex' => BSON::Regexp::Raw.new('^p') } }
                        ])
findObservable = collection.find(and(
  equal("status", "A"),
  or(lt("qty", 30), regex("item", "^p")))
)

The operation corresponds to the following SQL statement:

SELECT * FROM inventory WHERE status = "A" AND ( qty < 30 OR item LIKE "p%")

Note

MongoDB supports regular expressions $regex queries to perform string pattern matches.

Behavior

Cursor

The db.collection.find() method returns a cursor to the matching documents.

The MongoDB Compass Find operation opens a cursor to the matching documents of the collection based on the find query.

For more information on sampling in MongoDB Compass, see the Compass FAQ.

The pymongo.collection.Collection.find() method returns a cursor to the matching documents. See the PyMongo documentation for iterating over a cursor.

The com.mongodb.client.MongoCollection.find method returns an instance of the com.mongodb.client.FindIterable interface.

The Collection.find() method returns a cursor.

The MongoDB\Collection::find() method returns a cursor to the matching documents. See the MongoDB PHP Library documentation for iterating over a cursor.

The MongoCollection.Find() method returns a cursor to the matching documents. See the MongoDB C# driver documentation for iterating over a cursor.

The MongoDB::Collection::find() method returns a cursor to the matching documents. See the MongoDB Perl driver documentation for iterating over a cursor.

The Mongo::Collection#find() method returns a CollectionView, which is an Enumerable. A Cursor is created when the View is enumerated; for example, by calling #to_a() or #each(). You can also get an Enumerator by calling #to_enum() on the View. See the Ruby driver API documentation for iterating over a cursor.

The collection.find() method returns the find Observable.

Read Isolation

New in version 3.2.

For reads to replica sets and replica set shards, read concern allows clients to choose a level of isolation for their reads. For more information, see Read Concern.

Additional Methods

The following methods can also read documents from a collection:

Note

The db.collection.findOne() method also performs a read operation to return a single document. Internally, the db.collection.findOne() method is the db.collection.find() method with a limit of 1.

Additional Options

In addition to filter, MongoDB Compass also allows the following options to be passed to the query bar:

Project Specify which fields to return in the resulting data.
Sort Specify the sort order of the returned documents.
Skip Specify the first n-number of document to skip before returning the result set.
Limit Specify the maximum number of documents to return.

Additional Methods

The following methods can also read documents from a collection:

Note

The pymongo.collection.Collection.find_one() method also performs a read operation to return a single document. Internally, the pymongo.collection.Collection.find_one() method is the pymongo.collection.Collection.find() method with a limit of 1.

Additional Methods

The following methods can also read documents from a collection:

Additional Methods

The following methods can also read documents from a collection:

Note

The Collection.findOne() method also performs a read operation to return a single document. Internally, the Collection.findOne() method is the Collection.find() method with a limit of 1.

Additional Methods

The following methods can also read documents from a collection:

Note

The MongoDB\Collection::findOne() method also performs a read operation to return a single document. Internally, the MongoDB\Collection::findOne() method is the MongoDB\Collection::find() method with a limit of 1.

Additional Methods

The following methods can also read documents from a collection:

Additional Methods

The following methods can also read documents from a collection:

Note

The MongoCollection.FindOne() method also performs a read operation to return a single document. Internally, the MongoCollection.FindOne() method is the MongoCollection.Find() method with a limit of 1.

Additional Methods

The following methods can also read documents from a collection:

Note

The MongoDB::Collection::find_one() method also performs a read operation to return a single document. Internally, the MongoDB::Collection::find_one() method is the MongoDB::Collection::find() method with a limit of 1.

Additional Methods

The following methods can also read documents from a collection:

Additional Methods

The following methods can also read documents from a collection: