select
    SMS_R_SYSTEM.ResourceID,
    SMS_R_SYSTEM.ResourceType,
    SMS_R_SYSTEM.Name,
    SMS_R_SYSTEM.SMSUniqueIdentifier,
    SMS_R_SYSTEM.ResourceDomainORWorkgroup,
    SMS_R_SYSTEM.Client
from
    SMS_R_System
    inner join SMS_G_System_WORKSTATION_STATUS on SMS_G_System_WORKSTATION_STATUS.ResourceId = SMS_R_System.ResourceId
where
    SMS_G_System_WORKSTATION_STATUS.LastHardwareScan < Datediff(dd,Getdate(),-30)