What is the difference between the following two snippets (i.e LINQ Query vs Lambda Expression)

LINQ Query

public Product GetProduct(int productID)
{
    AdventureWorksDBDataContext db = new AdventureWorksDBDataContext();
    Product product = (from p in db.Products
                       where p.ProductID == productID
                       select p).Single();
    return product;
} 

Using a Lambda expression

public Product GetProduct(int productID)
{
    AdventureWorksDBDataContext db = new AdventureWorksDBDataContext();
    Product product = db.Products.Single(p => p.ProductID == productID);
    return product;
}