MongoDB pull with positional operator?

Use $pull operator along with positional operator($) in MongoDB. Let us first create a collection with documents −

> db.pullWithPositionalOperatorDemo.insertOne( ...   { ...      _id: 100, ...      "StudentDetails": [ ...         { ...            "StudentId": "STU-1", ...            "StudentFavouriteSubject": ["MongoDB", "Java"] ...         }, ...         { ...            "StudentId": "STU-2", ...            "StudentFavouriteSubject": ["PHP", "MySQL"] ...         } ...      ] ...   } ... ); { "acknowledged" : true, "insertedId" : 100 }

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

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

This will produce the following output −

{    "_id" : 100,    "StudentDetails" : [       {          "StudentId" : "STU-1",          "StudentFavouriteSubject" : [             "MongoDB",             "Java"          ]       },       {          "StudentId" : "STU-2",          "StudentFavouriteSubject" : [             "PHP",             "MySQL"          ]       }    ] }

Following is the query to perform pull with positional operator −

> db.pullWithPositionalOperatorDemo.update({ ...   "StudentDetails" : { ...      "$elemMatch" : { ...         "StudentId" : "STU-2", ...         "StudentFavouriteSubject" : "MySQL" ...      } ...   } ... }, { ...      $pull : { ...         "StudentDetails.$.StudentFavouriteSubject" : "MySQL" ...      } ... }, { ...    multi : true ... }); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Let us check all documents from the above collection once again −

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

This will produce the following output −

{    "_id" : 100,    "StudentDetails" : [       {          "StudentId" : "STU-1",          "StudentFavouriteSubject" : [             "MongoDB",             "Java"          ]       },       {          "StudentId" : "STU-2",          "StudentFavouriteSubject" : [             "PHP"          ]       }    ] }