Clients with a boot time > 31 Days

SELECT
    SMS_R_System.Name,
    SMS_R_System.SMSAssignedSites,
    SMS_R_System.IPAddresses,
    SMS_R_System.IPSubnets,
    SMS_R_System.ADSiteName,
    SMS_R_System.OperatingSystemNameandVersion,
    SMS_R_System.ResourceDomainORWorkgroup,
    SMS_R_System.LastLogonUserDomain,
    SMS_R_System.LastLogonUserName,
    SMS_R_System.SMSUniqueIdentifier,
    SMS_R_System.ResourceId,
    SMS_R_System.ResourceType,
    SMS_R_System.NetbiosName,
    SMS_R_System.ClientType,
    SMS_G_System_OPERATING_SYSTEM.LastBootUpTime
FROM
    SMS_R_System
    INNER JOIN SMS_G_System_OPERATING_SYSTEM ON SMS_G_System_OPERATING_SYSTEM.ResourceId = SMS_R_System.ResourceId
WHERE
    SMS_R_System.Client = 1
    AND DATEDIFF(
        DD,
        SMS_G_System_OPERATING_SYSTEM.LastBootUpTime,
        GetDate()
    ) > 31