select EMPLOYEE_ID
,job as POSITION
,UPDATE_DT as LAST_UPDATE_DT
from (
select EMPLOYEE_ID,job,UPDATE_DT,sheet,row_number()over(partition by employee_id order by update_dt desc,sheet) as rn
from (
select EMPLOYEE_ID,POSITION as job,LAST_UPDATE_DT as UPDATE_DT,1 sheet from EMPLOYEE_INFO
union all 
select EMPLOYEE_ID,NEW_POSITION as job,UPDATE_DT,2 sheet from EMPLOYEE_UPDATE
) t
) t
where rn=1
order by EMPLOYEE_ID