Praveen, Welcome to ROBOT.LK.
However I need to tell you few things as a new member.
1. Please use a descriptive subject. 'Help me' , 'Need help', etc... need to avoided. Read point (11) of
Terms of Use.
2. You were asking two different questions in one topic which is also not good. Next time, please use separate topics for different questions.
At the moment, lots of professionals around the globe have joined with us to waste some of their valuable time to help you. So you will have to respect these guidelines to reduce their time to understand your problem.
Okay, since you are a new user, I'll answer your questions. But I expect you will consider the above points next time
You can install Joomla or Drupal. You can add forums as plugins to both of these CMSs. phpBB can also be used as a plugin in a Joomla site.
There is a separate section to discuss theoretical parts (Computer Science) in SQL and Database at
Board index ‹ Engineering ‹ Computer Science ‹ SQL & Database.
Since mySQL is used usually combined with php, you can also find lots of information related to MySQL database under
Board index ‹ Programming ‹ Web programming ‹ PHP & MySQL. You will find some SQL tutorials there as well.