Getting a sum of unique inputs

[MYoung]

Hi all! First time poster, hoping someone can explain to me why I cannot figure this out based on my lurking on other threads.

I have a table (below) tracking information about tours we coordinate. We track the Presenters on each tour and a count field, so I can sum the total number of presenters across all our tours. However, I want to get the number of UNIQUE presenters across all the tours. e.g. if Vivaldi's Four Seasons and Romeo & Juliet both have "Shire of Cue" as a Presenter, how can I make sure it only gets counted once?

To make matter more complicated, I'm hoping to have this unique count number be on the same table as the rest of the information, because otherwise I can't access it easily when building a dashboard interface.

Appreciate any and all suggestions!

[TheTimeSavingCo]

Hmm, does the total number of records in the "Presenters" table output the number you're looking for?  If not, how are you determining what "All your tours" is?  

[MYoung]

I probably didn't provide enough information originally. I'm interested specifically in tours that are type "Shows On The Go". The Presenters table is a synced table from a base acting as our CRM. You can see how the entire Base for reporting is set up below.

I was able to create a rollup in that synced table from "Box Office Reports" (which is responses from Presenters per tour) rolling up "Presenters" and filtering for tours which are type "Shows On The Go".

I know that the Box Office Report table can give me the unique number of presenters, but I cannot figure out how to get that number into the "Tours" table. 

[TheTimeSavingCo · Accepted solution]

Ahh, yeah I see.  Hmm, given that the value already exists in Box Office Report, is it possible to just pull it over to Tours via lookup fields?  How are you planning on using that number in the dashboard?

I'm also surprised that you got ARRAYUNIQUE working like that; for me it just double counts the values

[MYoung]

You're so right - I already had the Box Office responses as a linked record in the Tours table, but linked records don't allow you a unique count, only "Filled/Empty", so I created a lookup field for the values and that worked. 

I believe it's something about the COUNTALL that allows ARRAYUNIQUE to work like that...I definitely run into issues if I try to create a lookup field in a different table of that field...

Thanks for your help!