delete from ITEM as i
where not exists (
    select 1
    from STOCK as s
    where s.ITEM_CODE = i.ITEM_CODE
)
or exists (
    select 1
    from STOCK as s
    where s.ITEM_CODE = i.ITEM_CODE
    and LAST_DELIVERY_DATE is not null
    and i.STOCK_MANAGEMENT_TYPE = 1
    group by s.ITEM_CODE
    having max(s.LAST_DELIVERY_DATE) <= '2023-06-01' - 6
    or s.ACTUAL_AMT = 0
);

select * from item left outer join stock on item.item_code = stock.item_code;