select 'ALTER table ' || owner ||'.' ||table_name || ' allocate extent;' as acc
from
(
select owner,table_name from dba_tables
where owner not in ('SYS','SYSTEM','DBSNMP','SYSMAN','WMSYS','ORDDATA','OLAPSYS','MDSYS','CTXSYS','APEX_030200','MDSYS','DVSYS','APPQOSSYS','GSMADMIN_INTERNAL','LBACSYS','OJVMSYS','DBSFWUSER','FLOWS_FILES','XDB','ORDSYS','OWBSYS','SCOTT')
minus
select owner,segment_name from dba_segments
);