This is what you will get when using the forecasting tool built into Tableau. It is found on the Analytics tab in the top, left corner.
I assumed that you have values for real and forecast in your data set. Also, I assumed you want to show real till today and forecast from today so that two values appear for today.
Here is workbook. Hope this helps.
Real & forecast_v10.2.twbx 44.0 KB
thank youfor your help ,
I want to use the forcasting data of tableau , i only have the reel value
yes this is the result of the forcasting tools of tableau
i want to have the reel and the forcasting data of tableau ( superimposed) on the same line graphe (what i add in black)
Tableau keeps a tight hold on their forecasting code and does not provide a ton of flexibility in this area. If you have forecast data of your own, you can be as creative as you like. If you are depending a the Tableau Forecast, then I think you get what you get.