SELECT
    CASE
        WHEN new.ITEM_CODE is not NULL THEN new.ITEM_CODE
        WHEN old.ITEM_CODE is not NULL THEN old.ITEM_CODE
        ELSE NULL
    END as CODE,
    
    CASE
        WHEN new.ITEM_CODE is not NULL THEN new.ITEM_NAME
        WHEN old.ITEM_CODE is not NULL THEN old.ITEM_NAME
        ELSE NULL
    END as NAME

,CASE
    WHEN new.ITEM_CODE is not NULL AND old.ITEM_CODE is NULL THEN 'ADDED' 
    WHEN new.ITEM_CODE is NULL AND old.ITEM_CODE is not NULL THEN 'DELETED'
    WHEN new.USER_UPDATE_DATETIME <> old.USER_UPDATE_DATETIME THEN 'UPDATED'    
    ELSE NULL
END as COMP_RSLT
FROM
    ITEM as new
    full outer join ITEM_HISTORY as old
    on new.ITEM_CODE = old.ITEM_CODE
WHERE
    COMP_RSLT is not NULL
ORDER BY
    CODE DESC