Hoe to convert a Sql Table into Xml file at runtime

I have a sql table like following structure ' Username UserID Subject Text abs 1 annoying asdasfasf niks 2 somethin asdhsfag

this table data is populating on page under responsive web design, what I want that when I go to page visit table data should convert into a xml file and fetch latest data from xml file. How can I implement this, please suggest me some idea.