I want a joomla component or module for product comparision...please advise me...

If you are thinking of doing this having a shopping cart software component, use: http://extensions.joomla.org/extensions/extension-specific/virtuemart-extensions/virtuemart-related-products/8010

If you are hesitant to make use of a shopping cart software and therefore are thinking of doing it more free-form, try: http://extensions.joomla.org/extensions/clients-a-communities/ratings-a-reviews/11305

Hope this can help!