Report for computers where the discovery agent time is older than 30 days

Report to list all the computer where the discovery agent time shows older than 30 days.

This you can find out if you right click on the computer ,go to properties and see Agent name[0] (ex:SMS_AD_SYSTEM_DISCOVERY) respect to Agent time[0] for the above discovery method which will be the recent date.

select a.Name0,b.AgentName,b.AgentTime from v_R_System a
join v_AgentDiscoveries b on b.ResourceId=a.ResourceId where
(AgentName  like 'Heartbeat Discovery' and DATEDIFF(Day,AgentTime,Getdate())>=30 ) OR
(AgentName  like 'SMS_AD_SYSTEM_DISCOVERY_AGENT' and DATEDIFF(Day,AgentTime,Getdate())>=30 )

group by name0 ,agentname,AgentTime

Order by Agentname

You can add other discovery methods if you enabled in your site to the above report.