Where is data coming from?
Thank you for your reply Dmitry.
The data is coming from Excel.
But I am not having permission to edit the Excel document.
If both tables are from the same file (same sheet or different sheet) then looks like you need to use our handy Union feature.
See nice into by one of my colleagues here: Combine Your Data with Union in Tableau 9.3 | Tableau Software
Once you've put table together ("one under the other") it will be easy to get to your desired result.