At the moment there's no way to rename a column when it's added to a viz. In many cases it's necessary to rename the columns because depending on the viz you might want to have a different label. Possibility of including variables/parameters like {current_month} in these column labels would be highly appreciated as well.
The only workaround at the moment is to include a custom calculation, replicating the same content as on the original column and change the name there but...time-consuming.
