SMS Report to list all the machines that haven't reported its discovery/inventory since past 30 days

select sys.Netbios_Name0,
sys.Client_Type0,
sys.Creation_date0 as 'Creation Date',
sys.Client_Version0,
sys.User_Domain0,
sys.User_Name0,
inst.sms_assigned_sites0 as 'sitecode',
disc.AgentTime as 'Last Discovery date',
hw.LastHWScan as 'Last HW Scan',
sw.LastScanDate as 'Last SW Scan'
from v_R_System sys
left join
(
select ResourceId, MAX(AgentTime) as AgentTime
from v_AgentDiscoveries
group by ResourceId
) as disc on disc.ResourceId = sys.ResourceID
left join v_GS_WORKSTATION_STATUS hw on hw.ResourceID = sys.ResourceID
left join v_GS_LastSoftwareScan sw on sw.ResourceID = sys.ResourceID
left join v_RA_System_SMSAssignedSites inst on inst.resourceid=sys.resourceid
where
disc.AgentTime < getdate()-30
or hw.LastHWScan < getdate()-30
or sw.LastScanDate < getdate()-30
and (sys.Client0 = 1 and sys.Obsolete0=0)
and sys.Name0 in (SELECT Name0
FROM v_r_system
GROUP BY Name0
HAVING COUNT(*) < 2)
order by disc.AgentTime asc