Thanks for your answer. Is there a way to do this without using pivot? This is actually a subset of the data and pivoting it might not be an option.
Yes, follow this example. http://www.evolytics.com/blog/tableau-201-how-to-compare-two-date-ranges-on-one-axis/
Sorry, this is a repeat of what you pointed out before. There are other examples that you may find easier to follow. Just go to Google and search "tableau two date ranges one axis".