select
    ITEM_CODE as CODE,
    ITEM_NAME as NAME,
    'ADDED' as COMP_RSLT
from
    ITEM
where ITEM_CODE not in
    (
        select
            ITEM_CODE
        from
            ITEM_HISTORY
    )
    
union

select
    ITEM_CODE as CODE,
    ITEM_NAME as NAME,
    'DELETED' as COMP_RSLT
from
    ITEM_HISTORY
where ITEM_CODE not in
    (
        select
            ITEM_CODE
        from
           ITEM 
    )
    
union

select
    ITEM_CODE as CODE,
    ITEM_NAME as NAME,
    'UPDATED' as COMP_RSLT
from
    (
    select
        *
    from
        ITEM
    where
        USER_UPDATE_DATETIME <> 
        (
        select
            USER_UPDATE_DATETIME
        from
            ITEM_HISTORY
        )
        and
        ITEM_CODE <>
        (
        select
            ITEM_CODE as CODE
        from
            ITEM
        where ITEM_CODE not in
            (
                select
                    ITEM_CODE
                from
                    ITEM_HISTORY
            )
        
        )
    );