Juha,

As of today, there is not an easy way to do this in Tableau Prep.  Here is an idea to vote to voice your support to the developers for future versions to make it easier : https://community.tableau.com/ideas/8793

For now, one approach I might consider would be to create a connection to the 2nd file only and in the Input Step make sure not to allow the first row to be used as column headers.  The automatic naming will be F1, F2, F3, etc...  It'll be a tedious process to rename each of those, but hopefully a one time process.  Assuming the 2nd file does not shift column positions when it's updated, then when you replace the file with a newer one, Tableau Prep will keep the naming convention and the change in names for each column.

Hope that helps!

Joshua

Hi Juha,

I just worked on a similar situation for someone else on this thread: Tableau Prep - generate headers from file It should help point you in the right direction.  Joshua Milligan is correct that there's no simple way of doing it in Tableau Prep today.  At least in the method described, it would be a (hopefully if the table headers don't change regularly) one-time setup and then you have a repeatable flow process.  Hope it helps..Thx!  Don