Nice work, you just defined ARPU for Mineblocks!

In our ARPU query, we used using instead of on in the join clause. This is a special case join.

from daily_revenue
  join daily_players using (dt);

When the columns to join have the same name in both tables you can use using instead of on. Our use of the using keyword is in this case equivalent to this clause:

from daily_revenue
  join daily_players on
    daily_revenue.dt = daily_players.dt;