MongoDB query to get only a specific number of elements

MongoDBDatabaseBig Data Analytics

To return only a specific number of elements, use aggregate() and $slice. Let us create a collection with documents −

> db.demo75.insertOne({"Name":["Sam","Mike","Carol","David","Bob","John"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e2bcd7671bf0181ecc42278")
}

Display all documents from a collection with the help of find() method −

> db.demo75.find();

This will produce the following output −

{ "_id" : ObjectId("5e2bcd7671bf0181ecc42278"), "Name" : [ "Sam", "Mike", "Carol", "David", "Bob", "John" ] }

Following is the slice query in MongoDB −

> db.demo75.aggregate([ { $project: { Name: { $slice: [ "$Name", 4 ] } } } ]);

This will produce the following output −

{ "_id" : ObjectId("5e2bcd7671bf0181ecc42278"), "Name" : [ "Sam", "Mike", "Carol", "David" ] }
raja
Published on 30-Mar-2020 08:03:36
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