MongoDB query to limit the returning values of a field?

For this, use $slice. Let us create a collection with documents −

> db.demo594.insertOne( ...    { ...       id:1, ...       details:[ ...          {Name:"Chris",Age:21}, ...          {Name:"Bob",Age:20}, ...          {Name:"David",Age:23}, ...          {Name:"Sam",Age:22} ...       ] ...    } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e933459fd2d90c177b5bcdd") }

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

> db.demo594.find();

This will produce the following output −

{ "_id" : ObjectId("5e933459fd2d90c177b5bcdd"), "id" : 1, "details" : [    { "Name" : "Chris", "Age" : 21 },    { "Name" : "Bob", "Age" : 20 },    { "Name" : "David", "Age" : 23 },    { "Name" : "Sam", "Age" : 22 } ] }

Following is the query to limit the returning values of a field −

> db.demo594.find({}, {"Name": 1, "details": { "$slice": 1}});

This will produce the following output −

{ "_id" : ObjectId("5e933459fd2d90c177b5bcdd"), "details" : [    { "Name" : "Chris", "Age" : 21 } ] }