Get distinct record values in MongoDB?

MongoDBDatabaseBig Data Analytics

You can use distinct() method in MongoDB to get distinct record values. The syntax is as follows −

db.yourCollectionName.distinct(“yourFieldName”);

To understand the above syntax, let us create a collection with document. The query to create a collection with document is as follows −

> db.distinctRecordDemo.insertOne({"StudentId":1,"StudentName":"John","StudentAge":21});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a78299b97a65744c1b50")
}
> db.distinctRecordDemo.insertOne({"StudentId":2,"StudentName":"John","StudentAge":22});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a78b99b97a65744c1b51")
}
> db.distinctRecordDemo.insertOne({"StudentId":3,"StudentName":"Carol","StudentAge":21});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a79a99b97a65744c1b52")
}
> db.distinctRecordDemo.insertOne({"StudentId":4,"StudentName":"Carol","StudentAge":26});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a7a499b97a65744c1b53")
}
> db.distinctRecordDemo.insertOne({"StudentId":5,"StudentName":"Sam","StudentAge":24});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a7b499b97a65744c1b54")
}
> db.distinctRecordDemo.insertOne({"StudentId":6,"StudentName":"Mike","StudentAge":27});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a7c799b97a65744c1b55")
}
> db.distinctRecordDemo.insertOne({"StudentId":7,"StudentName":"Sam","StudentAge":28});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c77a7d399b97a65744c1b56")
}

Display all documents from a collection with the help of find() method. The query is as follows −

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

The following is the output:

{
   "_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
}

Here is the query to get distinct records values in MongoDB.

Case 1 − Here the field is “StudentName”.

The query is as follows −

> db.distinctRecordDemo.distinct("StudentName");

The following is the output displaying distinct record for StudentName −

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

Case 2 − Here the field is “StudentAge”.

The query is as follows −

> db.distinctRecordDemo.distinct("StudentAge");

The following is the output displaying distinct record for StudentAge −

[ 21, 22, 26, 24, 27, 28 ]
raja
Published on 28-Mar-2019 11:17:37
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