Syntax error Getting distinct values from object array in MongoDB?

Getting distinct values from object array in MongoDB?



To get distinct values from object array in MongoDB, use distinct(). Let us create a collection with documents −

> db.demo442.insertOne(
...    {
...
...       "Information" : [
...          {
...             "FirstName" : "John",
...             "Age" : 21
...          },
...          {
...             "FirstName" : "Sam",
...             "Age" : 23
...          },
...          {
...             "FirstName" : "John",
...             "Age" : 24
...          },
...          {
...             "FirstName" : "Carol",
...             "Age" : 20
...          },
...          {
...             "FirstName" : "Sam",
...             "Age" : 22
...          }
...       ]
...    }
... );
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e78cf29bbc41e36cc3caeb8")
}

Display all documents from a collection with the help of find() method −

> db.demo442.find();

This will produce the following output −

{ "_id" : ObjectId("5e78cf29bbc41e36cc3caeb8"), "Information" : [ { "FirstName" : "John", "Age" : 21 }, { "FirstName" : "Sam", "Age" : 23 }, { "FirstName" : "John", "Age" : 24 }, { "FirstName" : "Carol", "Age" : 20 }, { "FirstName" : "Sam", "Age" : 22 } ] }

Following is the query to get distinct values from object array in MongoDB −

> db.demo442.distinct("Information.FirstName");

This will produce the following output −

[ "Carol", "John", "Sam" ]
Updated on: 2020-04-06T13:28:05+05:30

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