select 
  ifnull(ITEM.ITEM_CODE, hist.ITEM_CODE) as CODE,
  ifnull(ITEM.ITEM_NAME, hist.ITEM_NAME) as NAME,
  case 
    when ITEM.ITEM_CODE is null then 'DELETED' 
    when hist.ITEM_CODE is null then 'ADDED' 
    else 'UPDATED' 
  end as COMP_RSLT
from ITEM item
full outer join ITEM_HISTORY hist 
on   item.ITEM_CODE = hist.ITEM_CODE
where item.ITEM_CODE is null 
or    hist.ITEM_CODE is null
or    item.USER_UPDATE_DATETIME != hist.USER_UPDATE_DATETIME
order by 1 desc
;