Is it possible to return a list of specific values from a query in MongoDB?

MongoDBDatabaseBig Data Analytics

To return a list of specific values, use map(). Let us create a collection with documents −

> db.demo195.insertOne({"Subject":"MySQL"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e3af3f203d395bdc21346d4")
}
> db.demo195.insertOne({"Subject":"MongoDB"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e3af3f703d395bdc21346d5")
}
> db.demo195.insertOne({"Subject":"Java"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e3af3fa03d395bdc21346d6")
}

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

> db.demo195.find();

This will produce the following output −

{ "_id" : ObjectId("5e3af3f203d395bdc21346d4"), "Subject" : "MySQL" }
{ "_id" : ObjectId("5e3af3f703d395bdc21346d5"), "Subject" : "MongoDB" }
{ "_id" : ObjectId("5e3af3fa03d395bdc21346d6"), "Subject" : "Java" }

Following is the query to return a list of specific values from a query −

> db.demo195.find().map(function(doc){ return doc.Subject });

This will produce the following output −

[ "MySQL", "MongoDB", "Java" ]
raja
Published on 27-Mar-2020 14:27:06
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