If you are a serious Db2 user, chances are you have downloaded and used free Db2 versions for a few years. Db2 Express-C was a free way to learn Db2 on Linux, Unix and Windows, to practise and test your SQL skills and in later versions implement or ship Db2 with your small production application.
How to learn more about DB2? The answer is simple: DB2 Express-C, the community edition of DB2. You can learn, experiment and develop queries and applications through this easy to use and install version of DB2.