7D ARPU by country/device

example.sql

 SELECT install.os,
       install.country,
       Count(DISTINCT install.device_tag) AS installs,
       Count(DISTINCT economy.device_tag) AS spenders,
       Sum(economy.spend_amount)          AS total_spent
FROM   install
       LEFT OUTER JOIN economy
                    ON ( install.device_tag = economy.device_tag
                         AND economy.spend_type = 'cash_purchase'
                         AND Datediff('day', economy.ingest_datetime,
                             install.ingest_datetime) <= 7 )
WHERE  install.device_tag != 'missing'
       AND install.ingest_datetime < '2014-12-08'
       AND install.ingest_datetime >= '2014-12-07'
GROUP  BY 1,
          2
ORDER  BY 1 DESC,
          2 DESC
LIMIT  1000;