MongoDB query to pull array element from a collection?

Use the $pull operator to pull array element from a collection. Let us first create a collection with documents −

> db.pullElementFromAnArrayDemo.insertOne(
...    {
...       "StudentScores":[89,56,78,90]
...    }
... );
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cd0104a588d4a6447b2e063")
}

Following is the query to display all documents from a collection with the help of find() method −

> db.pullElementFromAnArrayDemo.find();

This will produce the following output −

{ "_id" : ObjectId("5cd0104a588d4a6447b2e063"), "StudentScores" : [ 89, 56, 78, 90 ] }

Following is the query to pull array element from a collection. Here, we are removing element 78 −

> db.pullElementFromAnArrayDemo.update({},{ $pull: { StudentScores: 78 } });
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Let us check the document once again −

> db.pullElementFromAnArrayDemo.find();

This will produce the following output −

{ "_id" : ObjectId("5cd0104a588d4a6447b2e063"), "StudentScores" : [ 89, 56, 90 ] }