DB2的with

with temptable(COMCODE,UPPERCOMCODE,Validstatus) 
 as  
(select root.COMCODE,root.UPPERCOMCODE,root.Validstatus 
from PRPDCOMPANY root where root.COMCODE=''
union all 
select sub.COMCODE,sub.UPPERCOMCODE,sub.Validstatus 
from 
PRPDCOMPANY sub,
temptable super 
where sub.UPPERCOMCODE=super.comcode 
and sub.comcode<>super.UpperComCode 
and sub.Validstatus = '1')
select COMCODE from temptable  ORDER BY ComCode