delete from ITEM 
where
not exists (
select 1 from stock s
where 
ITEM.item_code = s.item_code
)
or 
exists (
select 1 from stock s2
where 
ITEM.item_code = s2.item_code
and s2.LAST_DELIVERY_DATE >= datetime('2023-06-01','+6 month')
and ACTUAL_AMT=0
);