A tweet recently arrived from Pam Gidwani, to let me know that now everyone can make use of my Tableau Conference Television vis. Thank you Tableau, for making all of this amazing knowledge from TC14 available to the public!
Pam Gidwani on Twitter
Not surprisingly, page views on TC14-TV have rocketed up since then, as lots of folks are taking advantage of all the free know-how.
To celebrate, I'll explain some lovely features of how that workbook was put together.
About a ~year ago, I was still quite new to Tableau and I had a specific challenge: to build a Finder dashboard. The education I received from Jonathan Drummey was a real mind opener.
I discovered that so much more can be done once you begin construct your views in terms of logical building blocks. Thank you!
Brainstorming Multi-Select Filters: INTERSECTIO... | Tableau Support Community
The gist of the finder problem goes like this: in TC14-TV, for example, each session recording has multiple keywords.
And we sometimes want for a multi-select quick filter to find the intersection between the chosen keyword values. A multi-select quick filter in Tableau normally finds the union.
A Series of Calculations
To get there, Jonathan taught me to think in terms of logical building block calculations:
# Keywords for Session
Of the various keywords chosen, how many of those exist for each conference session?
# Keywords Selected
In total, how many keywords have been chosen in the quick-filter?
I've wrapped the total calculation in a PREVIOUS_VALUE() wrapper to improve performance. From number 10 in The Next N Table Calcs, this works because all rows will print the value from a single computation.
(PS - though, if I'm not mistaken, I understand now that TOTAL() behaves differently from most other table calcs & is computed only once, anyway :)
Keyword Intersection Filter
Now comes the good stuff. When filtering for the intersection, we only want conference sessions for which the[# Keywords for Session] >= [# Keywords Selected]
AND / OR
A parameter decides whether to use AND vs. OR logic. And there's a bit of an edge-case workaround, to help the intersection logic behave correctly when none of the conference sessions contain all of the keywords you're searching for.
That part about working around the edge-case is described in detail with my final update to our forum conversation.
The Finder Concept
In addition to highlighting the intersection logic, I really hope this post helps to illuminate the useful concept of a finder dashboard.
In short, a series of quick filters can help you to "find" the widgets you're searching for. And then, from that reduced list which match your criteria, the dashboard filter actions then bring other sheets into view.
This dashboard also gave me a chance to incorporate some Sheet Popping, which is explained very nicely by Joe Oppelt, Matthew Lutton, and Ville Tyrväinen in Sheet Swapping and Popping with Joe Oppelt (and a Tip on Searching the Tableau Forums).
So Why Wait ?
Not long now 'til TC15. Might I suggest we all commit to watching every session from TC14-TV before departing for TC15, Las Vegas in October ?
Word Count: 511
"Tableau Conference Television", Keith Helfrich, Redheaded Step Data, November 17, 2014
"About The Conference", TC14, Tableau, April 29, 2014
"Fantastic News", Tweet by Pam Gidwani, Twitter.com, April 20, 2015 11:43 AM
Jonathan Drummey, Data Blog, Drawing with Numbers, April 29, 2015
"Brainstorming Multi-Select Filters: