delete 
from 
    ITEM 
where 
    STOCK_MANAGEMENT_TYPE = 1 
    and 
    ITEM_CODE
        not in (
            select 
                ITEM_CODE 
            from 
                STOCK 
        ) 
    or 
    ITEM_CODE
        in (
            select 
                ITEM_CODE 
            from 
                STOCK 
            group by 
                ITEM_CODE 
            having 
                MAX(IFNULL(LAST_DELIVERY_DATE, '2999-12-31')) <= DATE ('2023-06-01', '-6 months') 
                and 
                sum(ACTUAL_AMT) < 1 
        ) 
;