How to query a nested document in mongo?

Retrieving an embedded document from the a mongo document?

• i had a mongo document structured as {    "id": 1,    "userId": 1,    "layout": 1,    "snapshotDetails"â–¼: {      "0": {        "id": 1,        "name": "jaison",        "type": "justus",        "width": 100,        "height": 100,        "position": 1     },      "1": {        "id": 2,        "name": "jatin",        "type": "justus",        "width": 100,        "height": 100,        "position": 2     }   },    "_id": ObjectId("4f58932309ac38f808000002") } and i need to extract the particular embedded document "1": {        "id": 2,        "name": "jatin",        "type": "justus",        "width": 100,        "height": 100,        "position": 2     }  under snapshotDetails. for that i build a query like db.MasterDashboard.find({ "userId" : 1, "http://snapshotDetails.id" : 1 }, { "snapshotDetails" : 1 }); But i am not getting the output properly. the output of the query is [ "0": {        "id": 1,        "name": "jaison",        "type": "justus",        "width": 100,        "height": 100,        "position": 1     },      "1": {        "id": 2,        "name": "jatin",        "type": "justus",        "width": 100,        "height": 100,        "position": 2     } ]   is any issue in my query. please help

• Answer:

  By default, MongoDB queries are designed to query entire http://documents.So when you run a find on this: { "userId" : 1, "http://snapshotDetails.id" : 1 } You are actually saying this: "find all documents with userId equal to 1 and having a snapshotDetail Id equal to 1" Now you also request a special return value: { "snapshotDetails" : 1 } And that's what you are getting back. You are getting the whole snapshotDetails field. What you actually want is the just the snapshotDetails that matched. Unfortunately, there is no way to do this. You can look at the docs here, you will see that feature simply does not exist. http://www.mongodb.org/display/DOCS/Retrieving+a+Subset+of+Fields You are not completely out of luck. If you take a look at the new Aggregation Framework, this has the features you need. http://www.mongodb.org/display/DOCS/Aggregation+Framework You should be able to do this with project and match.