I have some database questions and I would appreciate it if some one answered some of them:

1)What are the advantages of Oracle over mySQL?
2)Where does MS SQL Server stand when compared to Oracle and mySQL?
3)Is MS SQL Server as hard to learn as Oracle?
4)Does MS SQL Server have a good "front-end" like Access?
5)Is there a free version of Oracle?

As I said before I would really appreciate it if some one were to answer (some of) these questions