WQL Query for DDRHeartbeat Not send by last 14 days

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 where SMS_R_System.ResourceId not in (select ResourceID from SMS_R_System where AgentName in ("Heartbeat Discovery") and DATEDIFF(day,AgentTime,GetDate())<=14)