How can I search a collection to find a nested value in one of its documents in MongoDB?

For this, use double underscore( __) in find(). Let us first create a collection with documents −

> db.nestedDemo.insertOne({"Information":{"__StudentName":"John Smith"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06f39125ddae1f53b621f0") } > db.nestedDemo.insertOne({"Information":{"__StudentName":"John Doe"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06f39e25ddae1f53b621f1") } > db.nestedDemo.insertOne({"Information":{"__StudentName":"Chris Brown"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e06f3a625ddae1f53b621f2") }

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

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

This will produce the following output −

{    "_id" : ObjectId("5e06f39125ddae1f53b621f0"),    "Information" : {       "__StudentName" : "John Smith"    } } {    "_id" : ObjectId("5e06f39e25ddae1f53b621f1"),    "Information" : {       "__StudentName" : "John Doe"    } } {    "_id" : ObjectId("5e06f3a625ddae1f53b621f2"),    "Information" : {       "__StudentName" : "Chris Brown"    } }

Here is the query to search a collection to find a nested value in one of its documents in MongoDB −

> db.nestedDemo.find({"Information.__StudentName":"John Doe"});

This will produce the following output −

{ "_id" : ObjectId("5e06f39e25ddae1f53b621f1"), "Information" : { "__StudentName" : "John Doe" } }