In Tableau 9.2, I work with the "World Indicators" dataset, and notice that its Region field distinguishes "Middle East" as a region, alongside continents.
I rename Region to Region Raw, and create field Region by merging Region Raw values "Middle East" and "Asia" into group "Asia".
Wishing to produce a visualization for a specific region - and to play with Tableau parameters - I introduce parameter Selected Region.
I then place Region on Filters shelf, Edit Filter => Condition => By formula =>
max([Region]) == [Selected Region]
Oops: the visualization goes blank, no countries are shown. When I reopen the filter definition, I see
max([Region Raw]) == [Selected Region]
I fall back on creating a calculated field, Region Calculated
IF [Region Raw] = 'Middle East'
A filter based on Region Calculated "works", i.e. I see anon-blank visualization.
Do groups and filters - I figure the parameter is an innocent bystander here - really not get along in Tableau? If yes, can anyone point me to the relevant doc, or suggest the logic?
May we request for a sample .twbx file? so we can help you faster.