Why did you take all 150 files and put them into a common file instead of using a wildcard union option built into Tableau? You might also want to check out the Beta of Maestro. - Project Maestro | Tableau Software
Because I didn't know Tableau could do that...!
Thank you for the link
Great to hear. The wildcard Union is a great tool and very powerful way to manage many csv files. Enjoy and keep vizzing!
Thank you for the mark correct as well.