Sql 如何基于另一列生成索引列

例如，如果这里是

  Student        Course
---------------------------
student 1   |     Math
--------------------------
student 1   |     English
--------------------------
student 1   |     Art
--------------------------
student 2   |     Math
--------------------------
student 2   |     Economics
--------------------------
student 3   |     Math
--------------------------
student 3   |     English
--------------------------

我希望如何根据学生生成课程索引列，如下所示

  Student        Course       Index
--------------------------------------------
student 1   |     Math      |   1
--------------------------------------------
student 1   |     English   |   2
--------------------------------------------
student 1   |     Art       |   3
--------------------------------------------
student 2   |     Math      |   1
--------------------------------------------
student 2   |     Economics |   2
--------------------------------------------
student 3   |     Math      |   1
--------------------------------------------
student 3   |     English   |   2
--------------------------------------------

基本上，第二个表的第三列是每个学生的课程索引/顺序，但我希望第二个表成为Oracle中第二个表的查询，只是找不到解决方案。我只能算出总数，但不能算出索引。

就是你要找的

SELECT Student
       ,Course
       ,ROW_NUMBER() OVER (PARTITION BY Student ORDER BY Course DESC) AS "Index"
FROM your_table;

这就是你要找的

SELECT Student
       ,Course
       ,ROW_NUMBER() OVER (PARTITION BY Student ORDER BY Course DESC) AS "Index"
FROM your_table;

---

您需要使用行数窗口功能

select student, course, 
    Row_number() over (partition by student order by course) 
from the_table

---

您需要使用行数窗口功能

select student, course, 
    Row_number() over (partition by student order by course) 
from the_table

---

好吧，你需要引用索引，因为它是一个关键字。True@JoachimIsaksson。编辑，你被抢了。甚至连文档的链接都没有。没有正义-好吧，你需要引用索引，因为它是一个关键字。True@JoachimIsaksson。编辑，你被抢了。甚至连文档的链接都没有。没有正义-每个学生的课程顺序重要吗？每个学生的课程顺序重要吗？