Union Data in Tableau It looks difficult to union data in tableau if you want to Union data from different tables. And you'll be amazed once you know how easy to this in Tableau. You can achieve this by Manual way or automatic way. Specific unions Let use multiple sheets with the same number of columns and same type of data in them. I have three files A, B and C The data source window in Tableau – I have connected to my source but not brought in any sheets yet. I can union these three together simply by dragging them into the Data Pane one at a time. After adding the first one, the subsequent ones can be dragged beneath the first until the little orange box which reads “ Drag table to union ” appears. Drag a new sheet on top of the existing one until this appears… …then the data will be added as a union. Tableau will automatically append the rows onto the original, identifying matching fields by their shared name. Before union… …after unio...