Level of detail expressions
It happens often that you want to create calculated fields that aggregate data but you need them to be independent of the dimensions in your figure. You can do this by using the level of detail expressions.
Fixed
Use a fixed set of dimensions
Total population per country:
{FIXED continent, country : SUM(population) }
Exclude
Ignore a specific dimension in the vis
Total population per country:
{EXCLUDE city : SUM(population)}
Include
Add a specific dimension in the vis
Total population per country:
{INCLUDE country : SUM(population)}
Min(1) trick
http://datapsientist.blogspot.com/2014/10/tableau-trick-for-work-min1.html
Creating a Parameter Control to Sort By Dimension
https://kb.tableau.com/articles/howto/creating-a-parameter-control-to-sort-by-dimension
Send parameters from workbook to workbook via URL
https://community.tableau.com/thread/202493