DELETE 
FROM ITEM 
WHERE STOCK_MANAGEMENT_TYPE = 1 
  AND 
  ( 
    NOT EXISTS 
    ( 
        SELECT STOCK.ITEM_CODE 
        FROM STOCK 
        WHERE STOCK.ITEM_CODE = ITEM.ITEM_CODE
    ) 
    OR EXISTS ( 
        SELECT ITEM_CODE 
        FROM STOCK 
        WHERE STOCK.ITEM_CODE = ITEM.ITEM_CODE
        AND LAST_DELIVERY_DATE IS NOT NULL
        GROUP BY STOCK.ITEM_CODE 
        HAVING
                DATE ('2023-06-01', '-6 months') <= STOCK.LAST_DELIVERY_DATE
                AND SUM(STOCK.ACTUAL_AMT) = 0
        )
    );