Return specific MongoDB embedded document

Use $unwind twice for specific embedded document in MongoDB. Let us create a collection with documents −

> db.demo631.insert(
...    {
...       id: "101",
...       Info1: [
...          {
...             CountryName : "US",
...             Info2 : [
...                {
...                   Name:"Chris",
...                   Age:24
...                },{
...
...                      Name:"Bob",
..                     . Age:22
...                }
...             ]
...          }
...       ]
...    }
... );
WriteResult({ "nInserted" : 1 })

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

> db.demo631.find();

This will produce the following output −

{ "_id" : ObjectId("5e9b0eb16c954c74be91e6bf"), "id" : "101", "Info1" : [ { "CountryName" : "US", "Info2" : [ { "Name" : "Chris", "Age" : 24 }, { "Name" : "Bob", "Age" : 22 } ] } ] }

Following is the query to return specific MongoDB embedded document −

> db.demo631.aggregate([
...    { "$unwind": "$Info1" },
...    { "$unwind": "$Info1.Info2" },
...    { "$match": { "Info1.Info2.Age": 22 } }
... ])

This will produce the following output −

{ "_id" : ObjectId("5e9b0eb16c954c74be91e6bf"), "id" : "101", "Info1" : { "CountryName" : "US", "Info2" : { "Name" : "Bob", "Age" : 22 } } }

AmitDiwan

Published on 12-May-2020 10:51:09