PHP, MySQL Interview questions

1. What are the differences between PHP4 & PHP 5.
2. Give your ideas how you can scale up a LAMP based website.
3. Which design pattern is used by Symfony.
4. what is the difference between pass by value and pass by reference.
   
5. Describe the highlights of MVC architecture.
   
6. How many types of tables does MySQL have.
7. What are the differences between MyIASM and INNODB table types.
8. What could be a possible reason if someone is looking to store session information inside a database, what are the steps involved in doing the same.
9. How would you do clustering in MySQL.
10. What are the different types of Indexes in MySQL.
11. Explain FullText index in MySQL.
12. Can we overwrite a row using insert in MySQL if the primary key is unique.
13. Suggest some optimization steps in MySQL and sql queries.
14. How would you create a function which would accept variable number of inputs.