Since I started my new job, I’ve been implementing ConfigMgr 2012 in a number of sites.
This simple query has proven useful to get a reasonably accurate count of installed systems, after the initial system discovery is run. Useful to identify clients that may no longer be supported.
SELECT operating_system_name_and0 AS OSType,
Count(*) AS Total
GROUP BY operating_system_name_and0
ORDER BY operating_system_name_and0