with upd as (
select t1.* from item t1 join item_history t2 on t1.item_code=t2.item_code where t1.USER_UPDATE_DATETIME <>t2.USER_UPDATE_DATETIME 
)
, ins as (
select t1.* from item t1 left join item_history t2 on t1.item_code=t2.item_code where t2.item_code is null
)
, del as (
select t1.* from item_history t1 left join item t2 on t1.item_code=t2.item_code where t2.item_code is null
)



select item_code as CODE,
item_name as NAME,
x as COMP_RSLT
from (
select *,'UPDATED' as x from upd union all 
select *,'ADDED' as x from ins union all 
select *,'DELETED' as x from del
) as tbl


order by 1 desc;