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

Yes, you can return a list of specific values from a MongoDB query using the map() method or projection. The map() method transforms query results into an array of specific field values.

Syntax

db.collection.find().map(function(document){ 
    return document.fieldName; 
});

Sample Data

db.listOfSpecificValuesDemo.insertMany([
    {"StudentName": "John"},
    {"StudentName": "Chris"},
    {"StudentName": "Robert"},
    {"StudentName": "David"}
]);

{
    "acknowledged": true,
    "insertedIds": {
        "0": ObjectId("5cefcc8fef71edecf6a1f6bb"),
        "1": ObjectId("5cefcc94ef71edecf6a1f6bc"),
        "2": ObjectId("5cefcc98ef71edecf6a1f6bd"),
        "3": ObjectId("5cefcc9cef71edecf6a1f6be")
    }
}

View All Documents

db.listOfSpecificValuesDemo.find();

{ "_id": ObjectId("5cefcc8fef71edecf6a1f6bb"), "StudentName": "John" }
{ "_id": ObjectId("5cefcc94ef71edecf6a1f6bc"), "StudentName": "Chris" }
{ "_id": ObjectId("5cefcc98ef71edecf6a1f6bd"), "StudentName": "Robert" }
{ "_id": ObjectId("5cefcc9cef71edecf6a1f6be"), "StudentName": "David" }

Method 1: Using map() Function

Extract only the StudentName values as an array ?

db.listOfSpecificValuesDemo.find().map(function(myDocument){ 
    return myDocument.StudentName; 
});

[ "John", "Chris", "Robert", "David" ]

Method 2: Using Projection with distinct()

Alternative approach to get unique field values ?

db.listOfSpecificValuesDemo.distinct("StudentName");

[ "Chris", "David", "John", "Robert" ]

Conclusion

Use map() to transform query results into arrays of specific field values. For unique values only, distinct() is more efficient than map().