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Project Fields to Return from Query

By default, queries in MongoDB return all fields in matching documents. To limit the amount of data that MongoDB sends to applications, you can include a projection document to specify or restrict fields to return.

This page provides examples of query operations with projection 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 with projection 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 with projection using the com.mongodb.client.MongoCollection.find method in the 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 with projection 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 with projection 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 with projection 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 with projection 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 with projection 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 with projection 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", status: "A", size: { h: 14, w: 21, uom: "cm" }, instock: [ { warehouse: "A", qty: 5 } ] },
  { item: "notebook", status: "A",  size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "C", qty: 5 } ] },
  { item: "paper", status: "D", size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "A", qty: 60 } ] },
  { item: "planner", status: "D", size: { h: 22.85, w: 30, uom: "cm" }, instock: [ { warehouse: "A", qty: 40 } ] },
  { item: "postcard", status: "A", size: { h: 10, w: 15.25, uom: "cm" }, instock: [ { warehouse: "B", qty: 15 }, { warehouse: "C", qty: 35 } ] }
]);

You can run the operation in the web shell below:

db.inventory.insert_many([
    {"item": "journal",
     "status": "A",
     "size": {"h": 14, "w": 21, "uom": "cm"},
     "instock": [{"warehouse": "A", "qty": 5}]},
    {"item": "notebook",
     "status": "A",
     "size": {"h": 8.5, "w": 11, "uom": "in"},
     "instock": [{"warehouse": "C", "qty": 5}]},
    {"item": "paper",
     "status": "D",
     "size": {"h": 8.5, "w": 11, "uom": "in"},
     "instock": [{"warehouse": "A", "qty": 60}]},
    {"item": "planner",
     "status": "D",
     "size": {"h": 22.85, "w": 30, "uom": "cm"},
     "instock": [{"warehouse": "A", "qty": 40}]},
    {"item": "postcard",
     "status": "A",
     "size": {"h": 10, "w": 15.25, "uom": "cm"},
     "instock": [
         {"warehouse": "B", "qty": 15},
         {"warehouse": "C", "qty": 35}]}])
collection.insertMany(asList(
    Document.parse("{ item: 'journal', status: 'A', size: { h: 14, w: 21, uom: 'cm' }, instock: [ { warehouse: 'A', qty: 5 }]}"),
    Document.parse("{ item: 'notebook', status: 'A',  size: { h: 8.5, w: 11, uom: 'in' }, instock: [ { warehouse: 'C', qty: 5}]}"),
    Document.parse("{ item: 'paper', status: 'D', size: { h: 8.5, w: 11, uom: 'in' }, instock: [ { warehouse: 'A', qty: 60 }]}"),
    Document.parse("{ item: 'planner', status: 'D', size: { h: 22.85, w: 30, uom: 'cm' }, instock: [ { warehouse: 'A', qty: 40}]}"),
    Document.parse("{ item: 'postcard', status: 'A', size: { h: 10, w: 15.25, uom: 'cm' }, "
            + "instock: [ { warehouse: 'B', qty: 15 }, { warehouse: 'C', qty: 35 } ] }")
));
db.collection('inventory').insertMany([
  { item: "journal",
    status: "A",
    size: { h: 14, w: 21, uom: "cm" },
    instock: [ { warehouse: "A", qty: 5 } ]},
  { item: "notebook",
    status: "A",
    size: { h: 8.5, w: 11, uom: "in" },
    instock: [ { warehouse: "C", qty: 5 } ]},
  { item: "paper",
    status: "D",
    size: { h: 8.5, w: 11, uom: "in" },
    instock: [ { warehouse: "A", qty: 60 } ]},
  { item: "planner",
    status: "D",
    size: { h: 22.85, w: 30, uom: "cm"},
    instock: [ { warehouse: "A", qty: 40 } ]},
  { item: "postcard",
    status: "A",
    size: { h: 10, w: 15.25, uom: "cm" },
    instock: [
        { warehouse: "B", qty: 15 },
        { warehouse: "C", qty: 35 }]}
])
.then(function(result) {
  // process result
})
$insertManyResult = $db->inventory->insertMany([
    [
        'item' => 'journal',
        'status' => 'A',
        'size' => ['h' => 14, 'w' => 21, 'uom' => 'cm'],
        'instock' => [
            ['warehouse' => 'A', 'qty' => 5],
        ],
    ],
    [
        'item' => 'notebook',
        'status' => 'A',
        'size' => ['h' => 8.5, 'w' => 11, 'uom' => 'in'],
        'instock' => [
            ['warehouse' => 'C', 'qty' => 5],
        ],
    ],
    [
        'item' => 'paper',
        'status' => 'D',
        'size' => ['h' => 8.5, 'w' => 11, 'uom' => 'in'],
        'instock' => [
            ['warehouse' => 'A', 'qty' => 60],
        ],
    ],
    [
        'item' => 'planner',
        'status' => 'D',
        'size' => ['h' => 22.85, 'w' => 30, 'uom' => 'cm'],
        'instock' => [
            ['warehouse' => 'A', 'qty' => 40],
        ],
    ],
    [
        'item' => 'postcard',
        'status' => 'A',
        'size' => ['h' => 10, 'w' => 15.25, 'uom' => 'cm'],
        'instock' => [
            ['warehouse' => 'B', 'qty' => 15],
            ['warehouse' => 'C', 'qty' => 35],
        ],
    ],
]);
var documents = new[]
{
    new BsonDocument
    {
        { "item", "journal" },
        { "status", "A" },
        { "size", new BsonDocument { { "h", 14 }, { "w", 21 }, { "uom", "cm" } } },
        { "instock", new BsonArray
            {
                new BsonDocument { { "warehouse", "A" }, { "qty", 5 } } }
            }
    },
    new BsonDocument
    {
        { "item", "notebook" },
        { "status", "A" },
        { "size", new BsonDocument { { "h", 8.5 }, { "w", 11 }, { "uom", "in" } } },
        { "instock", new BsonArray
            {
                new BsonDocument { { "warehouse", "C" }, { "qty", 5 } } }
            }
    },
    new BsonDocument
    {
        { "item", "paper" },
        { "status", "D" },
        { "size", new BsonDocument { { "h", 8.5 }, { "w", 11 }, { "uom", "in" } } },
        { "instock", new BsonArray
            {
                new BsonDocument { { "warehouse", "A" }, { "qty", 60 } } }
            }
    },
    new BsonDocument
    {
        { "item", "planner" },
        { "status", "D" },
        { "size", new BsonDocument { { "h", 22.85 }, { "w", 30 }, { "uom", "cm" } } },
        { "instock", new BsonArray
            {
                new BsonDocument { { "warehouse", "A" }, { "qty", 40 } } }
            }
    },
    new BsonDocument
    {
        { "item", "postcard" },
        { "status", "A" },
        { "size", new BsonDocument { { "h", 10 }, { "w", 15.25 }, { "uom", "cm" } } },
        { "instock", new BsonArray
            {
                new BsonDocument { { "warehouse", "B" }, { "qty", 15 } },
                new BsonDocument { { "warehouse", "C" }, { "qty", 35 } } }
            }
    }
};
collection.InsertMany(documents);
$db->coll("inventory")->insert_many(
    [
        {
            item   => "journal",
            status => "A",
            size   => { h => 14, w => 21, uom => "cm" },
            instock => [ { warehouse => "A", qty => 5 } ]
        },
        {
            item   => "notebook",
            status => "A",
            size   => { h => 8.5, w => 11, uom => "in" },
            instock => [ { warehouse => "C", qty => 5 } ]
        },
        {
            item   => "paper",
            status => "D",
            size   => { h => 8.5, w => 11, uom => "in" },
            instock => [ { warehouse => "A", qty => 60 } ]
        },
        {
            item   => "planner",
            status => "D",
            size   => { h => 22.85, w => 30, uom => "cm" },
            instock => [ { warehouse => "A", qty => 40 } ]
        },
        {
            item    => "postcard",
            status  => "A",
            size    => { h => 10, w => 15.25, uom => "cm" },
            instock => [
                { warehouse => "B", qty => 15 },
                { warehouse => "C", qty => 35 }
            ]
        }
    ]
);
client[:inventory].insert_many([{ item: 'journal',
                                  status: 'A',
                                  size: { h: 14, w: 21, uom: 'cm' },
                                  instock: [ { warehouse: 'A', qty: 5 }] },
                                { item: 'notebook',
                                  status: 'A',
                                  size: { h: 8.5, w: 11, uom: 'in' },
                                  instock: [ { warehouse: 'C', qty: 5 }] },
                                { item: 'paper',
                                  status: 'D',
                                  size: { h: 8.5, w: 11, uom: 'in' },
                                  instock: [ { warehouse: 'A', qty: 60 }] },
                                { item: 'planner',
                                  status: 'D',
                                  size: { h: 22.85, w: 30, uom: 'cm' },
                                  instock: [ { warehouse: 'A', qty: 40 }] },
                                { item: 'postcard',
                                  status: 'A',
                                  size: { h: 10, w: 15.25, uom: 'cm' },
                                  instock: [ { warehouse: 'B', qty: 15 },
                                             { warehouse: 'C', qty: 35 }] }])
collection.insertMany(Seq(
  Document("""{ item: "journal", status: "A", size: { h: 14, w: 21, uom: "cm" }, instock: [ { warehouse: "A", qty: 5 } ] }"""),
  Document("""{ item: "notebook", status: "A",  size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "C", qty: 5 } ] }"""),
  Document("""{ item: "paper", status: "D", size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "A", qty: 60 } ] }"""),
  Document("""{ item: "planner", status: "D", size: { h: 22.85, w: 30, uom: "cm" }, instock: [ { warehouse: "A", qty: 40 } ] }"""),
  Document("""{ item: "postcard", status: "A", size: { h: 10, w: 15.25, uom: "cm" },
                instock: [ { warehouse: "B", qty: 15 }, { warehouse: "C", qty: 35 } ] }""")

)).execute()

Return All Fields in Matching Documents

If you do not specify a projection document, the db.collection.find() method returns all fields in the matching documents.

If you do not specify a projection document, the find() method returns all fields in the matching documents.

If you do not specify a projection, the com.mongodb.client.MongoCollection.find method returns all fields in the matching documents.

If you do not specify a projection document, the find() method yields all fields in the matching documents.

If you do not specify a projection document, the find() method returns all fields in the matching documents.

If you do not specify a projection filter, the MongoCollection.Find() method returns all fields in the matching documents.

If you do not specify a projection document, the find() method returns all fields in the matching documents.

If you do not specify a projection document, the find() method returns all fields in the matching documents.

If you do not specify a projection, the collection.find() method returns all fields in the matching documents.

The following example returns all fields from all documents in the inventory collection where the status equals "A":

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

The operation corresponds to the following SQL statement:

SELECT * from inventory WHERE status = "A"

Return the Specified Fields and the _id Field Only

A projection can explicitly include several fields by setting the <field> to 1 in the projection document. The following operation returns all documents that match the query. In the result set, only the item, status and, by default, the _id fields return in the matching documents.

db.inventory.find( { status: "A" }, { item: 1, status: 1 } )
cursor = db.inventory.find(
    {"status": "A"}, {"item": 1, "status": 1})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A")).projection(include("item", "status"));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ item: 1, status: 1 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['item' => 1, 'status' => 1]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Include("item").Include("status");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" }, { projection => { item => 1, status => 1 } }
);
client[:inventory].find({ status: 'A' },
                       projection: { item: 1, status: 1 })
findObservable = collection.find(equal("status", "A")).projection(include("item", "status"))

The operation corresponds to the following SQL statement:

SELECT _id, item, status from inventory WHERE status = "A"

Suppress _id Field

You can remove the _id field from the results by setting its exclusion <field> to 0 in the projection, as in the following example:

db.inventory.find( { status: "A" }, { item: 1, status: 1, _id: 0 } )
cursor = db.inventory.find(
    {"status": "A"}, {"item": 1, "status": 1, "_id": 0})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A"))
        .projection(fields(include("item", "status"), excludeId()));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ item: 1, status: 1, _id: 0 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['item' => 1, 'status' => 1, '_id' => 0]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Include("item").Include("status").Exclude("_id");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" }, { projection => { item => 1, status => 1, "_id" => 0 } }
);
client[:inventory].find({ status: 'A' },
                        projection: { item: 1, status: 1, _id: 0 })
findObservable = collection.find(equal("status", "A"))
  .projection(fields(include("item", "status"), excludeId()))

The operation corresponds to the following SQL statement:

SELECT item, status from inventory WHERE status = "A"

Return All But the Excluded Fields

Instead of listing the fields to return in the matching document, you can use a projection to exclude specific fields. The following example which returns all fields except for the status and the instock fields in the matching documents:

db.inventory.find( { status: "A" }, { status: 0, instock: 0 } )
cursor = db.inventory.find(
    {"status": "A"}, {"status": 0, "instock": 0})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A")).projection(exclude("item", "status"));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ status: 0, instock: 0 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['status' => 0, 'instock' => 0]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Exclude("status").Exclude("instock");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" }, { projection => { status => 0, instock => 0 } }
);
client[:inventory].find({ status: 'A' },
                        projection: { status: 0, instock: 0 })
findObservable = collection.find(equal("status", "A")).projection(exclude("item", "status"))

With the exception of the _id field, you cannot combine inclusion and exclusion statements in projection documents.

Return Specific Fields in Embedded Documents

You can return specific fields in an embedded document. Use the dot notation to refer to the embedded field and set to 1 in the projection document.

The following example returns: the _id field (returned by default), item field, status field, and the uom field in the size document; the uom field remains embedded in the size document.

db.inventory.find(
   { status: "A" },
   { item: 1, status: 1, "size.uom": 1 }
)
cursor = db.inventory.find(
    {"status": "A"}, {"item": 1, "status": 1, "size.uom": 1})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A")).projection(include("item", "status", "size.uom"));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ item: 1, status: 1, "size.uom": 1 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['item' => 1, 'status' => 1, 'size.uom' => 1]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Include("item").Include("status").Include("size.uom");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" }, { projection => { item => 1, status => 1, "size.uom" => 1 } }
);
client[:inventory].find({ status: 'A' },
                        projection: { 'item' => 1, 'status' => 1, 'size.uom' => 1 })
findObservable = collection.find(equal("status", "A")).projection(include("item", "status", "size.uom"))

Suppress Specific Fields in Embedded Documents

You can suppress specific fields in an embedded document. Use the dot notation to refer to the embedded field in the projection document and set to 0.

The following example specifies a projection to exclude the uom field inside the size document. All other fields are returned in the matching documents:

db.inventory.find(
   { status: "A" },
   { "size.uom": 0 }
)
cursor = db.inventory.find({"status": "A"}, {"size.uom": 0})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A")).projection(exclude("size.uom"));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ "size.uom": 0 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['size.uom' => 0]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Exclude("size.uom");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" }, { projection => { "size.uom" => 0 } }
);
client[:inventory].find({ status: 'A' },
                        projection: { 'size.uom' => 0 })
findObservable = collection.find(equal("status", "A")).projection(exclude("size.uom"))

Projection on Embedded Documents in an Array

Use dot notation to project specific fields inside documents embedded in an array.

The following example specifies a projection to return the item field, the status field, and the qty field in the documents embedded in the instock array. The _id field is returned by default.

db.inventory.find( { status: "A" }, { item: 1, status: 1, "instock.qty": 1 } )
cursor = db.inventory.find(
    {"status": "A"}, {"item": 1, "status": 1, "instock.qty": 1})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A")).projection(include("item", "status", "instock.qty"));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ item: 1, status: 1, "instock.qty": 1 });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['item' => 1, 'status' => 1, 'instock.qty' => 1]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Include("item").Include("status").Include("instock.qty");
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find( { status => "A" },
    { projection => { item => 1, status => 1, "instock.qty" => 1 } } );
client[:inventory].find({ status: 'A' },
                        projection: {'item' => 1, 'status' => 1, 'instock.qty' => 1 })
findObservable = collection.find(equal("status", "A")).projection(include("item", "status", "instock.qty"))

Project Specific Array Elements in the Returned Array

For fields that contain arrays, MongoDB provides the following projection operators: $elemMatch, $slice, and $.

The following example uses the $slice projection operator to return just the last element in the instock array.

db.inventory.find( { status: "A" }, { name: 1, status: 1, instock: { $slice: -1 } } )
cursor = db.inventory.find(
    {"status": "A"},
    {"item": 1, "status": 1, "instock": {"$slice": -1}})

To specify a projection document, chain the com.mongodb.client.FindIterable.projection method to the find method. The example uses the com.mongodb.client.model.Projections class to create the projection documents.

findIterable = collection.find(eq("status", "A"))
        .projection(fields(include("item", "status"), slice("instock", -1)));
var cursor = db.collection('inventory').find({ 
  status: "A"
}).project({ item: 1, status: 1, "instock": { $slice: -1 } });
$cursor = $db->inventory->find(
    ['status' => 'A'],
    ['projection' => ['item' => 1, 'status' => 1, 'instock' => ['$slice' => -1]]]
);
var filter = Builders<BsonDocument>.Filter.Eq("status", "A");
var projection = Builders<BsonDocument>.Projection.Include("item").Include("status").Slice("instock", -1);
var result = collection.Find<BsonDocument>(filter).Project(projection).ToList();
$cursor = $db->coll("inventory")->find(
    { status => "A" },
    { projection => { item => 1, status => 1, instock => { '$slice' => -1 } } }
);
client[:inventory].find({ status: 'A' },
                        projection: {'item' => 1,
                                     'status' => 1,
                                     'instock' => { '$slice' => -1 } })
findObservable = collection.find(equal("status", "A"))
  .projection(fields(include("item", "status"), slice("instock", -1)))

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. { "instock.0": 1 } projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. { "instock.0": 1 } projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. include("instock.0") projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. { "instock.0": 1 } projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. [ "instock.0" => 1 ] projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array.

For example, the following operation will not project the array with the first element:

Builders<BsonDocument>.Projection.Include("instock.0")

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. { "instock.0" => 1 } projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. { "instock.0" => 1 } projection will not project the array with the first element.

$elemMatch, $slice, and $ are the only way to project specific elements to include in the returned array. For instance, you cannot project specific array elements using the array index; e.g. include("instock.0") projection will not project the array with the first element.

See also

Query Documents

[1]You can use the DBQuery.shellBatchSize to change the number of iteration from the default value 20. See Working with the mongo Shell for more information.