delete from
    ITEM
where
    item_code in(
        select
            item_code
        from
            stock
        group by
            item_code
        having
            max(LAST_DELIVERY_DATE) < date('2023-06-01','-6 months')
    );

delete from
    item
where
    item_code not in(
        select
            distinct item_code
        from
            stock
    );