DELETE FROM
    ITEM
WHERE
    STOCK_MANAGEMENT_TYPE=1
    AND NOT EXISTS(
        SELECT 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 ACTUAL_AMT=0
            AND IFNULL(LAST_DELIVERY_DATE,'2999-12-31') <= DATE('2023-06-01','-6 months')
        );