Projection of one column in MongoDB?

Let us first create a collection with documents −

> db.demo216.insertOne({"ClientName":"John","ClientAge":34}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e351003d395bdc213470c") } > db.demo216.insertOne({"ClientName":"Bob","ClientAge":32}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e351703d395bdc213470d") } > db.demo216.insertOne({"ClientName":"Mike","ClientAge":35}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e351c03d395bdc213470e") }

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

> db.demo216.find();

This will produce the following output −

{ "_id" : ObjectId("5e3e351003d395bdc213470c"), "ClientName" : "John", "ClientAge" : 34 } { "_id" : ObjectId("5e3e351703d395bdc213470d"), "ClientName" : "Bob", "ClientAge" : 32 } { "_id" : ObjectId("5e3e351c03d395bdc213470e"), "ClientName" : "Mike", "ClientAge" : 35 }

Following is the query to project only a single column −

> db.demo216.find({},{_id:0,"ClientAge":0});

This will produce the following output −

{ "ClientName" : "John" } { "ClientName" : "Bob" } { "ClientName" : "Mike" }