MySQL a wildly used SQL(structured query language) engine for the web had been around for more than eight (8) years already (as of this writing) and have greatly improved in terms of Stability, Flexibility, Capacity to handle, maintain, fetch, process information in a more timely manner.   

This version is based on 3.23 or 4.x and covers the most common SQL statements that might work with MSSQL, Interbase, Oracle and so on.   

There are many SQL flavors out in the market today.    Most of those are upgrades or revision from other older SQL engines that existed earlier and where said to be in BETA or at it's early stages.     Features would varies depending on the purpose it was build upon.   Some performs better in one platform from the other.

MySQL is one of the very, very few SQL engines build for the Web and performs real well, for Multi-User roles.  

SQL - structured query language, is an industry standard language specifically designed to enable people to create databases.

DBMS - a DataBase Management System, is a set of programs used to define, administer and process DAtabases and their associated applications.