MongoDB query to pull a specific value from a document

MongoDBDatabaseBig Data Analytics

To pull a specific value, use UPDATE with $pull. Let us create a collection with documents −

> db.demo318.insertOne({Subject:["MySQL","MongoDB","Java"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e50ea6df8647eb59e562062")
}
> db.demo318.insertOne({Subject:["Spring","Hibernate"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e50ea78f8647eb59e562063")
}

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

> db.demo318.find();

This will produce the following output −

{ "_id" : ObjectId("5e50ea6df8647eb59e562062"), "Subject" : [ "MySQL", "MongoDB", "Java" ] }
{ "_id" : ObjectId("5e50ea78f8647eb59e562063"), "Subject" : [ "Spring", "Hibernate" ] }

Following is the query to $pull a specific value “Hibernate” −

> db.demo318.update({Subject:"Hibernate"},{$pull:{"Subject":"Hibernate"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

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

> db.demo318.find();

This will produce the following output −

{ "_id" : ObjectId("5e50ea6df8647eb59e562062"), "Subject" : [ "MySQL", "MongoDB", "Java" ] }
{ "_id" : ObjectId("5e50ea78f8647eb59e562063"), "Subject" : [ "Spring" ] }
raja
Published on 02-Apr-2020 09:38:44
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