DELETE FROM ITEM
WHERE (ITEM_CODE NOT IN (SELECT ITEM_CODE FROM STOCK) OR 
        ITEM_CODE IN (SELECT ITEM_CODE 
                    FROM (SELECT ITEM_CODE, MAX(LAST_DELIVERY_DATE) MAXDATE, ACTUAL_AMT
                        FROM STOCK 
                        GROUP BY ITEM_CODE)
                    WHERE MAXDATE < DATE('2023-06-01', '-6 months') 
                        AND ACTUAL_AMT = 0)
    )
    AND STOCK_MANAGEMENT_TYPE = 1