For searching value, use $match in MongoDB. Let us create a collection with documents −
> db.demo648.insertOne( ... { ... StudentInformation: ... [ ... { ... Name:"John", ... CountryName:"US" ... }, ... { ... Name:"David", ... CountryName:"AUS" ... }, ... { ... Name:"Chris", ... CountryName:"US" ... }, ... { ... Name:"Robert", ... CountryName:"UK" ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e9c8b286c954c74be91e6f5") }
Display all documents from a collection with the help of find() method −
> db.demo648.find();
This will produce the following output −
{ "_id" : ObjectId("5e9c8b286c954c74be91e6f5"), "StudentInformation" : [ { "Name" : "John", "CountryName" : "US" }, { "Name" : "David", "CountryName" : "AUS" }, { "Name" : "Chris", "CountryName" : "US" }, { "Name" : "Robert", "CountryName" : "UK" } ] }
Following is the query to search for value in MongoDB −
> db.demo648.aggregate([ ... { $unwind: "$StudentInformation" }, ... { $match: { "StudentInformation.CountryName": "US" } }, ... { $project: {_id: 0}} ... ])
This will produce the following output −
{ "StudentInformation" : { "Name" : "John", "CountryName" : "US" } } { "StudentInformation" : { "Name" : "Chris", "CountryName" : "US" } }