"Finally, Tableau does not support combining data from two workbooks (or data sources in general) into a single Tableau view. This is a feature request that we've heard in the past and we are considering it for future development."
Year of the message is 2008. Is there any development about this issue after that date?
I want to join two excel sheets of different workbooks, but cannot.
I can join for now only if the two are in the same workbook.
Are you talking about two Excel sheets that are in two different Excel workbooks? If this is the case, then, no currently, it is not possible to join the two sheets unless they are from the same file. This might be a good one to add to the Ideas section!