delete
from ITEM
where
    ITEM_CODE in (
        (
        select i.ITEM_CODE
        from ITEM i left join STOCK s on i.ITEM_CODE = s.ITEM_CODE
        group by i.ITEM_CODE
        having
            s.ITEM_CODE is null
        or
            (
                sum(s.ACTUAL_AMT) = 0
            and
                max(s.LAST_DELIVERY_DATE) <= date('now', '-6 months')
            )
        )
    )
and
    STOCK_MANAGEMENT_TYPE = 1
;