Is there a difference between these two lambda expressions?

Question

What is the difference if any between these two Lambda Expressions ? And the second one seems more compact should I always go for that ?

DataContext.Employee.Where(c=>c.id==check_id && c.username==user_name).Select(c=>c.Name).FirstOrDefault();

and

DataContext.Employee.FirstOrDefault(c=>c.id==check_id && c.username==user_name).Name;

Answer 1

The second version can throw a NullReferenceException if a matching element is not found and the default value for the type is null.

The first version does not have this problem.