题解 | 更新员工信息表

# 直接union all 开窗取最新

    select employee_id as EMPLOYEE_ID , new_position as  POSITION,update_dt as LAST_UPDATE_DT

    from 
    (
    select employee_id , update_dt, new_position ,
    row_number()over(partition by employee_id order by update_dt desc,flg) as rn
    from (
      select employee_id , update_dt, new_position,2 as  flg
      from EMPLOYEE_UPDATE
      union all
      select employee_id , last_update_dt, position,1 as flg
      from EMPLOYEE_INFO
    )t
    )t where rn=1