Resolution

Create the parameter

1. In the Parameters pane, right-click and select Create > Parameter....
2. For Data Type, select String.
3. For Allowable values, select List.
4. In the List of values add the dimension members of the desired field to be filtered.
5. Click Click to add new value to manually add the value "All".

Create a calculated field

1. Navigate to Analysis > Create calculated field....
2. Enter a formula similar to the following: [Dimension to be Filtered] = [Parameter] OR [Parameter] = 'All').
3. Drag the new calculated field to the Filters shelf and select True.

Additional Information

• Add an All to a parameter in Tableau
• Tableau Tip: Adding an “All” filter option to a string parameter