Display only a single field from all the documents in a MongoDB collection

To display only a single field from all documents in a MongoDB collection, use projection in the find() method. Set the desired field to 1 to include it, or set unwanted fields to 0 to exclude them.

Syntax

db.collection.find({}, {fieldName: 1, _id: 0});
// OR
db.collection.find({}, {unwantedField1: 0, unwantedField2: 0});

Sample Data

db.demo384.insertMany([
    {"StudentName": "Chris Brown", "StudentCountryName": "US"},
    {"StudentName": "David Miller", "StudentCountryName": "AUS"},
    {"StudentName": "John Doe", "StudentCountryName": "UK"}
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e5b67a022064be7ab44e7f2"),
        ObjectId("5e5b67ab22064be7ab44e7f3"),
        ObjectId("5e5b67b422064be7ab44e7f4")
    ]
}

Display all documents to see the complete structure ?

db.demo384.find();

{ "_id": ObjectId("5e5b67a022064be7ab44e7f2"), "StudentName": "Chris Brown", "StudentCountryName": "US" }
{ "_id": ObjectId("5e5b67ab22064be7ab44e7f3"), "StudentName": "David Miller", "StudentCountryName": "AUS" }
{ "_id": ObjectId("5e5b67b422064be7ab44e7f4"), "StudentName": "John Doe", "StudentCountryName": "UK" }

Method 1: Include Only Desired Field

Display only StudentName by setting it to 1 and excluding _id ?

db.demo384.find({}, {StudentName: 1, _id: 0});

{ "StudentName": "Chris Brown" }
{ "StudentName": "David Miller" }
{ "StudentName": "John Doe" }

Method 2: Exclude Unwanted Fields

Display only StudentCountryName by excluding other fields ?

db.demo384.find({}, {_id: 0, StudentName: 0});

{ "StudentCountryName": "US" }
{ "StudentCountryName": "AUS" }
{ "StudentCountryName": "UK" }

Key Points

• Use fieldName: 1 to include specific fields (inclusion projection)
• Use fieldName: 0 to exclude specific fields (exclusion projection)
• Always exclude _id with _id: 0 unless you need it
• Cannot mix inclusion and exclusion (except for _id)

Conclusion

MongoDB projection allows you to control which fields appear in query results. Use {fieldName: 1, _id: 0} for inclusion or {unwantedField: 0} for exclusion to display only the required single field.