如何获得在每个科目中获得最高分的学生的姓名? [英] How to get the name of a the student who got max marks in each subject?

问题描述

我有下表

 Name  |  Subject  | Marks
 --------------------------
 a        M          20
 b        M          25  
 c        M          30
 d        C          44 
 e        C          45
 f        C          46 
 g        H          20

这里我有一个学生"表，我想获取获得的学生的姓名
学生表中每个科目的最高分数，如下面的输出.

Here I have a "Student" table I want to get the Name of the student who got
Max marks from each subject from the student table like the following OUTPUT.

 Name | Subject | Marks  
 c        M        30
 f        c        46
 g        h        20

推荐答案

您可以使用 ROW_NUMBER 函数仅返回每个主题的最佳"行:

You can use the ROW_NUMBER function to return only the "best" row per subject:

SQL 小提琴

MS SQL Server 2008 架构设置:

CREATE TABLE Student
    ([Name] varchar(1), [Subject] varchar(1), [Marks] int)
;

INSERT INTO Student
    ([Name], [Subject], [Marks])
VALUES
    ('a', 'M', 20),
    ('b', 'M', 25),
    ('c', 'M', 30),
    ('d', 'C', 44),
    ('e', 'C', 45),
    ('f', 'C', 46),
    ('g', 'H', 20)
;

查询 1:

SELECT Name, Subject, Marks
FROM(
  SELECT *, ROW_NUMBER()OVER(PARTITION BY Subject ORDER BY Marks DESC) rn
    FROM dbo.Student
)X
WHERE rn = 1

结果:

| NAME | SUBJECT | MARKS |
--------------------------
|    f |       C |    46 |
|    g |       H |    20 |
|    c |       M |    30 |

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