查询每个班级排名第三的学生

Posted 2022-01-21 ShenLiang2025

需求描述

有两张表，想要查询每个班级排名第三的学生。排名按照总成绩排（数学+英语）。表结构如图：

student表：

score表：

mysql version 5.5 or 8.0.

希望大家帮我写两个版本的。谢谢大家了

---

数据：

student表：

1 name1 class1

2 name2 class1

3 name3 class1

4 name4 class1

5 name5 class2

6 name6 class2

7 name7 class2

8 name8 class2

score表：

1 1 English 100

2 1 Math 95

3 2 English 96

4 2 Math 95

5 3 English 100

6 3 Math 99

7 4 English 98

8 4 Math 97

9 5 English 99

10 5 Math 95

11 6 English 96

12 6 Math 94

13 7 English 92

14 7 Math 100

15 8 English 97

16 8 Math 95

解决方法

-- #1 建表语句及初始化脚本
CREATE TABLE stu
(id SMALLINT,
name varchar(12),
className varchar(12)
)

CREATE TABLE score
(id SMALLINT,
stu_id varchar(12),
courseName varchar(12),
courseScore SMALLINT
)


INSERT INTO stu VALUES ('1','name1','class1');
INSERT INTO stu VALUES ('2','name2','class1');
INSERT INTO stu VALUES ('3','name3','class1');
INSERT INTO stu VALUES ('4','name4','class1');
INSERT INTO stu VALUES ('5','name5','class2');
INSERT INTO stu VALUES ('6','name6','class2');
INSERT INTO stu VALUES ('7','name7','class2');
INSERT INTO stu VALUES ('8','name8','class2');


INSERT INTO score VALUES ('1','1','English','100');
INSERT INTO score VALUES ('2','1','Math','95');
INSERT INTO score VALUES ('3','2','English','96');
INSERT INTO score VALUES ('4','2','Math','95');
INSERT INTO score VALUES ('5','3','English','100');
INSERT INTO score VALUES ('6','3','Math','99');
INSERT INTO score VALUES ('7','4','English','98');
INSERT INTO score VALUES ('8','4','Math','97');
INSERT INTO score VALUES ('9','5','English','99');
INSERT INTO score VALUES ('10','5','Math','95');
INSERT INTO score VALUES ('11','6','English','96');
INSERT INTO score VALUES ('12','6','Math','94');
INSERT INTO score VALUES ('13','7','English','92');
INSERT INTO score VALUES ('14','7','Math','100');
INSERT INTO score VALUES ('15','8','English','97');
INSERT INTO score VALUES ('16','8','Math','95');

-- #2 Mysql 8.0
SELECT * FROM
(
	SELECT *,ROW_NUMBER()OVER(PARTITION BY className ORDER BY total DESC) rn
	FROM
	(
	SELECT B.id,B.className,SUM(courseScore) total FROM score A
	JOIN stu B
	ON B.id = A.stu_id
	WHERE A.courseName IN('Math','English')
	GROUP BY B.id
	ORDER BY B.className,total DESC
	)A
)B	
WHERE rn<=3


-- #3 Mysql 5.5
SELECT * FROM
(
	select id,className,total,rank from (
		select className,heyf_tmp.id,heyf_tmp.total,@rownum := @rownum+1 ,
		if(@pdept= heyf_tmp.className,@rank:=@rank +1, @rank:= 1) as rank,
		@pdept:=heyf_tmp.className
		from ( 
			SELECT B.id,B.className,SUM(courseScore) total FROM score A
			JOIN stu B
			ON B.id = A.stu_id
			WHERE A.courseName IN('Math','English')
			GROUP BY B.id
			ORDER BY B.className,total DESC
		) heyf_tmp ,
		(select @rownum:=0 , @pdept:= null ,@rank:= 0) a
		order by className asc ,total desc
	) result
)	A
WHERE A.rank<=3
order by className,rank;

-- #4 结果
/*
id	className	total	rank
3	class1	        199	1
1	class1	        195	2
4	class1	        195	3
5	class2	        194	1
7	class2	        192	2
8	class2	        192	3

*/

执行结果