Solution: Merging Documents

// Picking Furniture products from products collection
db.products.aggregate([
  {
    $match: {
      category: "Furniture"
    }
  },
  {
    $merge: {
      into: "furniture",  // Adding matched products to a new collection
      whenMatched: "keepExisting",
      whenNotMatched: "insert"
    }
  }
]),
// Deleting Furniture products from the original products collection
db.products.deleteMany({
  category: "Furniture"
}),
// Fetch documents from the FurnitureProducts collection
db.furniture.find()