Rolling MAU computation

[Tom Hubina]

I'm trying to compute the number of active users in the previous 30 days
for each day over a date range. I can't think of any way to do it directly
within Hive so I'm wondering if you guys have any ideas.

Basically the algorithm is something like:

For each day in date range:
   SELECT day, COUNT(DISTINCT(userid)) FROM logins WHERE day - logins.day <
30;

Thanks for your help!

Tom