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MongoDB Aggregate to limit the number of records
To limit the number of records, use $limit in MongoDB. Let us create a collection with documents −
> db.demo240.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e441d969af932883c61ea3c") } > db.demo240.insertOne({"StudentName":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5e441d9a9af932883c61ea3d") } > db.demo240.insertOne({"StudentName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e441d9d9af932883c61ea3e") } > db.demo240.insertOne({"StudentName":"Mike"}); { "acknowledged" : true, "insertedId" : ObjectId("5e441da19af932883c61ea3f") }
Display all documents from a collection with the help of find() method −
> db.demo240.find();
This will produce the following output −
{ "_id" : ObjectId("5e441d969af932883c61ea3c"), "StudentName" : "Chris" } { "_id" : ObjectId("5e441d9a9af932883c61ea3d"), "StudentName" : "Bob" } { "_id" : ObjectId("5e441d9d9af932883c61ea3e"), "StudentName" : "David" } { "_id" : ObjectId("5e441da19af932883c61ea3f"), "StudentName" : "Mike" }
Following is the query to limit the number of records in MongoDB −
> db.demo240.aggregate( { $limit : 3 });
This will produce the following output −
{ "_id" : ObjectId("5e441d969af932883c61ea3c"), "StudentName" : "Chris" } { "_id" : ObjectId("5e441d9a9af932883c61ea3d"), "StudentName" : "Bob" } { "_id" : ObjectId("5e441d9d9af932883c61ea3e"), "StudentName" : "David" }
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