In case someone finds this question and still is seeking the solution!
I had a similar need. The use case was a unique list of employees whose records each included a single, concatenated field of all of the cities they'd visited in the year. (The underlying data was correctly shaped with a distinct record for each city visited, but the client wanted a particular display view that worked great for them.)
So the client wanted a table that looked like this:
EMPLOYEE CITIES VISITED
Person A London
Person B London,Paris
Person C Geneva
Person D Geneva,London,Milan
The easiest way for the client to find everyone who had visited London would have been to include a wildcard search filter. As soon as they typed London, the corresponding "Cities Visited" records would have appeared for them to select. However, the client wanted a filter option with preset cities they could click (rather than freehand entry of city names because they didn't want to guess what all the options were OR risk spelling errors).
Turns out it was very easy to do this using a parameter control, with many thanks to Dave Rawlings in the Tableau Community Forums (https://community.tableau.com/thread/210796)! I am not the OP from the post whom Dave assisted, but I was delighted to find it.
1) Create a list of unique options for the filter: I removed dupes in the underlying data to generate a unique list of cities visited. (The OP here would just use a list of states or state abbreviations.)
2) Create a parameter to create your filter options:
- On the bottom left of the worksheet, create a new parameter. I called mine "Cities."
- Type is String, Value Options are from a List.
- Add your unique options one-by-one to the List. I also included an option called "All."
- Set the Current Value to "All."
3) Create a calculated field to regulate the parameter. I named mine "CityFilter" and used this formula to set either "All" or the selected city to "Yes."
If [Cities]="All" THEN "Yes"
ELSEIF FIND([CitiesVisited],[Cities])> 0 THEN "Yes" ELSE "No" END
Here, "Cities" refers to the city the user has selected from the parameter list, and "CitiesVisited" refers to the concatenated field in the record with multiple/comma-separated values.
4) Create a filter from the calculated field: Drag the field to add to your filters: Set the required value to "Yes."
5) Display the parameter as a worksheet filter: Right-click the parameter to "Show Parameter." This adds it to the list of filters to the right of your worksheet.
6) Display the parameter as a dashboard filter: On your dashboard, on the upper right-hand side of one of your views, choose the Down arrow, then choose "Parameters." Select the parameter you created to add it to the filters list on the dash, too.
Reminder, as of now, parameters are single-select only, so the client only can filter to one city at a time! The multi-select, dynamic parameters Tableau are developing are focused on parameters across multiple data sources, rather than for multiple values within one field. That is because, in theory, this is bad data-ing. But if an example like this helps a client understand and leverage the data, I'm happy to oblige.
I hope this answers the original question for the OP or anyone else who could use a quick solution for a project!
