秩（）

A RANK() 返回分区列结果集中每行的等级。

例如：

Select Studentid,Name,Subject,Marks,
RANK() over(partition by name order by Marks desc)Rank
From Exam
order by name,subject

   Studentid    Name    Subject    Marks    Rank

    101         Ivan    Maths       70       2
    101         Ivan    Science     80       1
    101         Ivan    Social      60       3
    102         Ryan    Maths       60       2
    102         Ryan    Science     50       3
    102         Ryan    Social      70       1
    103         Tanvi   Maths       90       1
    103         Tanvi   Science     90       1
    103         Tanvi   Social      80       3