[{_id:ObjectId("661fb9ddc2b236ae8703ba92"),display_id:"38bd6126-02a1-47b9-b567-00aaf2eb076f",user_id:ObjectId("661137f22a31832ceb92ddbc"),items:[{product_id:ObjectId("6622376051d5886f39ac7365"),size:ObjectId("660d444d0d7716ee24129675"),qty:3},{product_id:ObjectId("662214f8cc5306f999369e99"),size:ObjectId("660d444d0d7716ee24129675"),qty:2},{product_id:ObjectId("662214f8cc5306f999369e99"),size:ObjectId("660d444d0d7716ee24129674"),qty:2}],__v:4}]

db.collection.aggregate([{"$match":{"user_id":ObjectId("661137f22a31832ceb92ddbc"),"items.product_id":ObjectId("662214f8cc5306f999369e99"),"items.size":ObjectId("660d444d0d7716ee24129675")}},{"$unwind":"$items"},{"$match":{"items.product_id":ObjectId("662214f8cc5306f999369e99"),"items.size":ObjectId("660d444d0d7716ee24129675")}},{"$replaceRoot":{"newRoot":"$items"}}])