Solution for this from tableau support for any who are interested -
The instructions for creating the view in the workbook are below. These instructions use our sample Superstore Excel data source. It may be helpful to test creating the view with that data source first and then applying the concept to your own workbook.
1. Right-click in the blank area under Dimensions or Measures
2. Select Create Calculated Field...
3. Name the field: Index
4. Enter the formula: INDEX()
5. Click OK
6. Place Order Date on the Rows shelf
7. Right-click on the YEAR(Order Date) pill on the Rows shelf and select Month
8. Place Product Name on the Rows shelf
9. Place Sales on the Text shelf of the Marks card
10. Place Index on the Rows shelf
11. Right click on the Index pill on the Rows shelf and select Discrete. (choose Compute Using> Table (Down))
12. Click and drag the Index pill in front of the MONTH(Order Date) pill on the Rows shelf
13. Right-click on the Index pill on the Rows shelf and uncheck Show in Header
14. Right-click on the Index pill on the Rows shelf and uncheck Include in Tooltip.