How to create a count for different subdomains?
My analytics domain holds a system in which users can create their own subdomains. They all share the same analytics code, so the data gets aggregated into the same account but the subdomain URL is maintained. I want to count how many different subdomains have had more than 20 user sessions in the last 30 days, but Data Studio won't let me create a calculated variable mixing metrics and dimensions.
How can I achieve this? Also, could I configure this to use a date control so I can dynamically change the 30 day period of time? Ideally this should produce a simple number that I could show in a scorecard field.