delete from ITEM as it
where 
    STOCK_MANAGEMENT_TYPE = 1 and
    not exists (select ITEM_CODE from STOCK as st where it.ITEM_CODE = st.ITEM_CODE) or
    exists (select ITEM_CODE from STOCK as st where it.ITEM_CODE = st.ITEM_CODE group by ITEM_CODE
            having max(ifnull(LAST_DELIVERY_DATE,'9999-12-12')) <= date('2023-06-01', '-6 months') and sum(ACTUAL_AMT) = 0);