How to return only value of a field in MongoDB?

To return only the values of a field in MongoDB, you can use projection with find() to select specific fields, or use forEach with an array to extract field values into a simple array format.

Syntax

// Method 1: Using projection
db.collection.find({}, { "fieldName": 1, "_id": 0 });

// Method 2: Using forEach to extract values
var output = [];
db.collection.find().forEach(function(doc) { 
    output.push(doc.fieldName); 
});

Sample Data

db.returnOnlyValueOfFieldDemo.insertMany([
    { "ClientName": "Larry" },
    { "ClientName": "Chris" },
    { "ClientName": "Robert" },
    { "ClientName": "Ramit" }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5c9ea537d628fa4220163b6e"),
        ObjectId("5c9ea53bd628fa4220163b6f"),
        ObjectId("5c9ea541d628fa4220163b70"),
        ObjectId("5c9ea549d628fa4220163b71")
    ]
}

Method 1: Using Projection (Recommended)

Return only the ClientName field values without the _id ?

db.returnOnlyValueOfFieldDemo.find({}, { "ClientName": 1, "_id": 0 });

{ "ClientName": "Larry" }
{ "ClientName": "Chris" }
{ "ClientName": "Robert" }
{ "ClientName": "Ramit" }

Method 2: Using forEach to Extract Values

Extract field values into a simple array using forEach ?

var output = [];
db.returnOnlyValueOfFieldDemo.find().forEach(function(document) {
    output.push(document.ClientName);
});
output;

[ "Larry", "Chris", "Robert", "Ramit" ]

Key Differences

Conclusion

Use projection with find() to return documents with only specific fields, or use forEach to extract field values into a simple array format. Projection is more efficient for displaying results, while forEach is useful for data processing.