LINQ: Query a collection within a collection

Question

I have following structure:

public class Customer
{
  public int ID { get; set; }
  public List<Order> Orders { get; set; }
}

public class Order
{
  public int ID { get; set; }
  public int ProductID { get set; }
}

I need to get the collection of customers that ordered ProductID = 6. What would the fluent style LINQ look like?

I tried below with no luck:

var customers = allCustomers.SelectMany(c => c.Orders.Select(o => o.ProductID.Equals(6))).ToArray();

Answer 1

var customers = allCustomers.Where(c => c.Orders.Any(o => o.ProductID == 6));