SELECT
 ITEM_CODE AS CODE
,ITEM_NAME AS NAME
CASE
if item_code NOT IN (SELECT item_code FROM ITEM)
AS DELETED

else ITEM_HISTORY.user_update_datetime <> ITEM.user_update_datetime
AS UPDATED
else 
FROM ITEM_HISTORY
JOIN ITEM ON ITEM_HISTORY.item_code = ITEM.item_code
SELECT 'DELETED' AS ChangeType, *
FROM ITEM
WHERE item_code NOT IN (SELECT item_code FROM ITEM_HISTORY);