SQL Server 2000 only works on Windows-based platforms, including Windows 9x, Windows NT, Windows 2000 and Windows CE. In comparison with SQL Server 2000, MySQL version 4.1 supports all known platforms, including Windows-based platforms, AIX-based systems, HP-UX systems, Linux Intel, Sun Solaris and so on. http://www.mssqlcity.com/Articles/Compare/sql_server_vs_mysql.htm I hope this will help you.
In structure wise both mysql and sql are same . sql are available only in windows platform and it is query structured language. While mysql is platform indepedent it is available at linux also. And most is myql is free database software
SQL is the language it self that can run on different platforms, MYSQL is the microsoft platform There are many paltforms out there, like oracle, DB2, mysql, etc..
SQL Server 2005 only works on Windows-based platforms, including Windows 9x, Windows NT, Windows 2000 and Windows CE. In comparison with SQL Server 2000, MySQL version 4.1 supports all known platforms, including Windows-based platforms mysql is a open source , sql is not mostiy mysql used in php;