How to hide _id from Aggregation?

To hide _id from aggregation, use the below syntax −

db.yourCollectionName.aggregate(    {$project : {       _id : 0 ,       yourIncludeFieldName:1,       yourIncludeFieldName:1    }} ).pretty();

To understand the above syntax, let us create a collection with the document. The query to create a collection with a document is as follows −

> db.hideidDemo.insertOne({"UserName":"Larry","UserAge":23,"UserCountryName":"US"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c92b02336de59bd9de06392") } > db.hideidDemo.insertOne({"UserName":"Chris","UserAge":21,"UserCountryName":"AUS"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c92b03036de59bd9de06393") } > db.hideidDemo.insertOne({"UserName":"Robert","UserAge":26,"UserCountryName":"UK"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c92b04036de59bd9de06394") }

Display all documents from a collection with the help of find() method. The query is as follows −

> db.hideidDemo.find().pretty();

The following is the output −

{    "_id" : ObjectId("5c92b02336de59bd9de06392"),    "UserName" : "Larry",    "UserAge" : 23,    "UserCountryName" : "US" } {    "_id" : ObjectId("5c92b03036de59bd9de06393"),    "UserName" : "Chris",    "UserAge" : 21,    "UserCountryName" : "AUS" } {    "_id" : ObjectId("5c92b04036de59bd9de06394"),    "UserName" : "Robert",    "UserAge" : 26,    "UserCountryName" : "UK" }

Here is the query to hide _id from aggregation −

> db.hideidDemo.aggregate(    ... {$project : {       ... _id : 0 ,       ... UserName:1,       ... UserCountryName:1    ... }} ... ).pretty();

The following is the output −

{ "UserName" : "Larry", "UserCountryName" : "US" } { "UserName" : "Chris", "UserCountryName" : "AUS" } { "UserName" : "Robert", "UserCountryName" : "UK" }