Running Total Distinct over time

user16684

Hi!

I have data for trainings/sessions that have been held over the last year, specifically who attended them.

I would like to visualize how many more unique attendees we are having every session, on each internal team. When I do a distinct count of attendees over time (a running total line graph), it gives me the running total sum of distinct attendees for each session, not session to session. The main question I would like to answer is: are the same people attending these sessions? Or are we attracting new people that are attending? If new people are attending, what team are they on?

Is what I am trying to visualize possible in Domo?

 

Here is an example use case:
Mary and Bill from Team A attended Session #1
Alex from Team B attended Session #1

Mary, Bill, and Jane attended Session #2

Alex from Team B attended Session #2

Team A had 2 unique attendees in Session #1 
Team B had 1 unique attendee in Session #1

 

Team A had 1 unique attendee in Session #2, Running Total: 3

Team B had 0 unique attendees in Session #2, Running Total: 1

user16684

I think I might use something like this in a MySql transform:

 

SELECT *
, (SELECT COUNT(1) FROM `attendees` p
WHERE p.`Email`=s.`Email`
AND p.`Event Date`<s.`Event Date`
) AS 'Previous Attendance Count'
FROM `attendees` s

 

This will give me a count of how many sessions they have attended, with the first one being '0'. Anything greater than 0 can be a non-unique attendee.