I am looking for some online service like - SQL Fiddle - http://sqlfiddle.com but with better features. SQL Fiddle limits the database size to a small sample and does not have any proper user features to manage the fiddles systematically "like having a method of proper tags or comments about each fiddle etc."

It should allow me to quickly create a demo database online and then experiment with various queries on it. I did some searching online and found that there are quite a lot of such services available, like -

http://www.hongkiat.com/blog/tools-to-coding-online/
http://techslides.com/30-code-playgrounds-and-sharing-tools

But it is not possible for me to manually tryout all of them. So I was looking for some tried and tested solution, which is already being used by a lot of users here.

Please suggest the best options in this regards, from your own experience.

Thanks a lot

Need to go for express/free evaluation editions of sql server. 

https://www.microsoft.com/en-in/download/details.aspx?id=29066