Computers reported Hardware Inventory within past 30 minutes

select a.Netbios_name0, a.Creation_date0,a.User_name0,a.client0, a.ad_site_name0,a.obsolete0,b.sms_installed_sites0 as 'sitecode',c.Lasthwscan
from v_r_system a
left outer join v_RA_System_SMSInstalledSites b on a.resourceid=b.resourceid
left outer join v_GS_WORKSTATION_STATUS c on a.resourceid=c.resourceid
where c.Lasthwscan >=DATEADD(minute,-30,GETDATE())
and c.Lasthwscan <= GETDATE()
Order by c.Lasthwscan desc