DELETE 
FROM
    ITEM AS I 
WHERE
    I.STOCK_MANAGEMENT_TYPE = 1 
    AND NOT EXISTS ( 
        SELECT
              1 
        FROM
            STOCK S 
        WHERE
            I.ITEM_CODE = S.ITEM_CODE
    ); 

DELETE 
FROM
    ITEM AS I 
WHERE
    I.STOCK_MANAGEMENT_TYPE = 1 
    AND EXISTS ( 
        SELECT
              1 
        FROM
            ( 
                SELECT
                      ITEM_CODE
                    , MAX(LAST_DELIVERY_DATE) AS LAST_DELIVERY_DATE 
                    , MAX(ACTUAL_AMT) AS ACTUAL_AMT
                FROM
                    STOCK 
                GROUP BY
                    ITEM_CODE
            ) S 
        WHERE
            I.ITEM_CODE = S.ITEM_CODE 
            AND S.LAST_DELIVERY_DATE <= DATE ('2023-06-01', '-6 months') 
            AND S.ACTUAL_AMT = 0
    );