Always welcome Murali. Once you completely discuss everything about this topic and once you feel that you have covered everything possible in this topic, start another unique/special topic and start growing it in the same way you have done this. Then we will move on to the next one and so on. The more we have these types of informative threads, the more will be our traffic and popularity.
Yeah i know that we are getting there prasath, in fact we are in the 2nd page in .com results
group_concat in MySQL - Google Search
Lets get to the first soon, move on to the next topic and do the same.
Good Luck!