unable to run query in oem db

Hi,

I am trying to hit this query against oem repo db but it gives error.Any pointers please

select sum(MAX_FILE_SIZE/1024/1024/1024) ,a.target_name,b.host_name from mgmt$db_datafiles a group by a.target_name,MGMT$STORAGE_REPORT_NFS b where  a.HOST_NAME=b.target_name and (sum(MAX_FILE_SIZE/1024/1024/1024))>(SIZEB/1024/1024/1024) and a.OS_STORAGE_ENTITY=b.MOUNTPOINT

                                                                                                                                                              *

ERROR at line 1:

ORA-00933: SQL command not properly ended

Best regards,

Vishal