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