ROW_NUMBER(),不允许并列名次、相同值名次不重复,结果如123456……
将score按ID分组排名:row_number() over(partition by id order by score desc)
将score不分组排名:row_number() over(order by score desc)
select id,area,score,
row_number() over(partition by id order by score desc) 分组id排序,
row_number() over(order by score desc) 不分组排序
from students order by id,area;