DistinctCount of the Distinct Count (Unique variables across three tables)

[rehabguru]

Dear collective gurus

Thank you for your advice...I have three separate tables containing non sensitive appointment details for three clinics. I can perform a distinctcount(tableone[HealthID]) / two / three etc to get the unique number of different people attending each clinic. My question relates to the overlap of clinics. How do I calculate the number of unique people attending all of the clinics combined?

I am sure FILTER pops in there somewhere but it clearly isn't the distinctcount of the distinctcounts - if you see what I mean. In a Venn diagramm it would be the people who feature in either one, two or all three clinics.
I am happy to provide a table if this elaborates but I am positive the collective brainpower will solve this in a heartbeat (one of the clinics by the way )

Many thanks

Dougie

 

[alansidman]

Why not append each table so that for analysis purposes you have one table. Then run your distinct count against the aggregated table.

 

[rehabguru]

Thank you very much Alansidman. Sorted ?