Get distinct record values in MongoDB?

The distinct() method in MongoDB returns unique values for a specified field across all documents in a collection, automatically removing duplicates.

Syntax

db.collectionName.distinct("fieldName");

Sample Data

db.distinctRecordDemo.insertMany([
    {"StudentId": 1, "StudentName": "John", "StudentAge": 21},
    {"StudentId": 2, "StudentName": "John", "StudentAge": 22},
    {"StudentId": 3, "StudentName": "Carol", "StudentAge": 21},
    {"StudentId": 4, "StudentName": "Carol", "StudentAge": 26},
    {"StudentId": 5, "StudentName": "Sam", "StudentAge": 24},
    {"StudentId": 6, "StudentName": "Mike", "StudentAge": 27},
    {"StudentId": 7, "StudentName": "Sam", "StudentAge": 28}
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5c77a78299b97a65744c1b50"),
        ObjectId("5c77a78b99b97a65744c1b51"),
        ObjectId("5c77a79a99b97a65744c1b52"),
        ObjectId("5c77a7a499b97a65744c1b53"),
        ObjectId("5c77a7b499b97a65744c1b54"),
        ObjectId("5c77a7c799b97a65744c1b55"),
        ObjectId("5c77a7d399b97a65744c1b56")
    ]
}

View Sample Data

db.distinctRecordDemo.find().pretty();

{
    "_id": ObjectId("5c77a78299b97a65744c1b50"),
    "StudentId": 1,
    "StudentName": "John",
    "StudentAge": 21
}
{
    "_id": ObjectId("5c77a78b99b97a65744c1b51"),
    "StudentId": 2,
    "StudentName": "John",
    "StudentAge": 22
}
{
    "_id": ObjectId("5c77a79a99b97a65744c1b52"),
    "StudentId": 3,
    "StudentName": "Carol",
    "StudentAge": 21
}
{
    "_id": ObjectId("5c77a7a499b97a65744c1b53"),
    "StudentId": 4,
    "StudentName": "Carol",
    "StudentAge": 26
}
{
    "_id": ObjectId("5c77a7b499b97a65744c1b54"),
    "StudentId": 5,
    "StudentName": "Sam",
    "StudentAge": 24
}
{
    "_id": ObjectId("5c77a7c799b97a65744c1b55"),
    "StudentId": 6,
    "StudentName": "Mike",
    "StudentAge": 27
}
{
    "_id": ObjectId("5c77a7d399b97a65744c1b56"),
    "StudentId": 7,
    "StudentName": "Sam",
    "StudentAge": 28
}

Example 1: Distinct Student Names

Get unique student names from the collection ?

db.distinctRecordDemo.distinct("StudentName");

["John", "Carol", "Sam", "Mike"]

Example 2: Distinct Student Ages

Get unique ages from the collection ?

db.distinctRecordDemo.distinct("StudentAge");

[21, 22, 26, 24, 27, 28]

Conclusion

The distinct() method efficiently retrieves unique values for any field, eliminating duplicates automatically. It returns an array containing only the distinct values found across all documents in the collection.