Get distinct values from a column in MongoDB?

To get distinct values from a column in MongoDB, use the distinct() method. This eliminates duplicate values and returns only unique values from the specified field.

Syntax

db.collection.distinct("fieldName")

Sample Data

Let us create a collection with documents that contain duplicate names ?

db.demo128.insertMany([
    {"Name": "Chris"},
    {"Name": "David"},
    {"Name": "David"},
    {"Name": "Bob"},
    {"Name": "Chris"}
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e30583d68e7f832db1a7f5d"),
        ObjectId("5e30584068e7f832db1a7f5e"),
        ObjectId("5e30584368e7f832db1a7f5f"),
        ObjectId("5e30584668e7f832db1a7f60"),
        ObjectId("5e30584c68e7f832db1a7f61")
    ]
}

Display all documents from the collection ?

db.demo128.find();

{ "_id": ObjectId("5e30583d68e7f832db1a7f5d"), "Name": "Chris" }
{ "_id": ObjectId("5e30584068e7f832db1a7f5e"), "Name": "David" }
{ "_id": ObjectId("5e30584368e7f832db1a7f5f"), "Name": "David" }
{ "_id": ObjectId("5e30584668e7f832db1a7f60"), "Name": "Bob" }
{ "_id": ObjectId("5e30584c68e7f832db1a7f61"), "Name": "Chris" }

Example: Get Distinct Values

Get distinct values from the Name field ?

db.demo128.distinct("Name");

[ "Bob", "Chris", "David" ]

Key Points

• The distinct() method returns an array of unique values
• Duplicate values are automatically removed from the result
• Results are sorted alphabetically by default

Conclusion

Use db.collection.distinct("fieldName") to retrieve unique values from any field in MongoDB. This method efficiently eliminates duplicates and returns a clean array of distinct values.