MongoDB findById returning a list of documents instead of a single result? How to get only a single document?

To get only a single result, use findOne() and fetch on the basis of id. Let us create a collection with documents −

> db.demo340.insertOne({_id:1,"Name":"Chris",Age:21});
{ "acknowledged" : true, "insertedId" : 1 }
> db.demo340.insertOne({_id:2,"Name":"David",Age:23});
{ "acknowledged" : true, "insertedId" : 2 }
> db.demo340.insertOne({_id:3,"Name":"Bob",Age:20});
{ "acknowledged" : true, "insertedId" : 3 }
> db.demo340.insertOne({_id:4,"Name":"Sam",Age:19});
{ "acknowledged" : true, "insertedId" : 4 }

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

> db.demo340.find();

This will produce the following output −

{ "_id" : 1, "Name" : "Chris", "Age" : 21 }
{ "_id" : 2, "Name" : "David", "Age" : 23 }
{ "_id" : 3, "Name" : "Bob", "Age" : 20 }
{ "_id" : 4, "Name" : "Sam", "Age" : 19 }

Here is the query to findby id −

> db.demo340.findOne({_id:1});

This will produce the following output −

{ "_id" : 1, "Name" : "Chris", "Age" : 21 }