For this, use $project in MongoDB. Within that, use $filter. Let us create a collection with documents −
> db.demo457.insertOne( ... { ... _id: 101, ... details: [ ... { ProductName:"Product-1" , ProductPrice:90 }, ... { ProductName:"Product-2" , ProductPrice:190 } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : 101 } > > db.demo457.insertOne( ... { ... _id: 102, ... details: [ ... { ProductName:"Product-3" , ProductPrice:150}, ... { ProductName:"Product-4" , ProductPrice:360 } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : 102 }
Display all documents from a collection with the help of find() method −
> db.demo457.find();
This will produce the following output −
{ "_id" : 101, "details" : [ { "ProductName" : "Product-1", "ProductPrice" : 90 }, { "ProductName" : "Product-2", "ProductPrice" : 190 } ] } { "_id" : 102, "details" : [ { "ProductName" : "Product-3", "ProductPrice" : 150 }, { "ProductName" : "Product-4", "ProductPrice" : 360 } ] }
Following is the query to return a document with filtered sub-documents using MongoDB −
> db.demo457.aggregate([ ... { ... $project: { ... details: { ... $filter: { ... input: "$details", ... as: "output", ... cond: { $gte: [ "$$output.ProductPrice", 170 ] } ... } ... } ... } ... } ... ])
This will produce the following output −
{ "_id" : 101, "details" : [ { "ProductName" : "Product-2", "ProductPrice" : 190 } ] } { "_id" : 102, "details" : [ { "ProductName" : "Product-4", "ProductPrice" : 360 } ] }