What are the differences between MySQL and Sql server? What are the parameter to chose between the two?
Several questions here related to DB comparisons of various flavors:
http://stackoverflow.com/questions/481879/what-are-the-major-differences-between-databases
http://stackoverflow.com/questions/404776/why-isnt-postgresql-as-widespread-as-mysql
http://stackoverflow.com/questions/195353/where-to-find-a-good-reference-when-choosing-a-database
http://stackoverflow.com/questions/216601/postgressql-mysql-oracle-diferences
The paramater to choose between the two is the price tag. How much do you "expect" to pay for your database. If its zero then MySQL is probably good enough for you, if its 10k then SQL Server is probably good enough for you.
As for the actual differences, there are too many to list.
http://www.eggheadcafe.com/community/aspnet/13/10017564/difference-between-mysql.aspx refer this site