Mysql多表练习题30道

根据上一篇文章建立的表,我们来做一些多表练习:

没建立表的可以点击此链接去建立练习用的表:

目录

1.查询“1”号学生的姓名和各科成绩:

2.查询各个学科的平均成绩和最高成绩:

3.查询所有姓张的同学的各科成绩:

4.查询每个同学的最高成绩和科目名称

5.查询每个课程的最高分的学生信息

6.查询名字中含有'张'或'李'字的学生的信息和各科成绩。

7.查询平均成绩大于70的同学的信息。(子查询)

8.将学生按照总分数进行排名。(从高到低)

9.查询数学成绩的最高分、最低分、平均分。

10.将各科目按照平均分排序。

11.查询老师的信息和他所带的科目的平均分

12.查询被"Tom"和"Jerry"教的课程的最高分和最低分

13.查询每个学生的最好成绩的科目名称(子查询)

14.查询所有学生的课程及分数

15.查询课程编号为1且课程成绩在60分以上的学生的学号和姓名(子查询)

16. 查询平均成绩大于等于70的所有学生学号、姓名和平均成绩

17.查询有不及格课程的学生信息

18.查询每门课程有成绩的学生人数

19.查询每门课程的平均成绩,结果按照平均成绩降序排列,如果平均成绩相同,再按照课程编号升序排列

20.查询平均成绩大于60分的同学的学生编号和学生姓名和平均成绩

21.查询有且仅有一门课程成绩在80分以上的学生信息

22.查询出只有三门课程的学生的学号和姓名

23.查询有不及格课程的课程信息

24.查询至少选择4门课程的学生信息

25.查询没有选全所有课程的同学的信息

26.查询选全所有课程的同学的信息 

27.查询各学生都选了多少门课

28.查询课程名称为"java",且分数低于60分的学生姓名和分数

29.查询学过"Tony"老师授课的同学的信息

30.查询没学过"Tony"老师授课的学生信息


1.查询“1”号学生的姓名和各科成绩:

进行student表和scores表的id相连接,course表和scores表的id相连接

SELECT
	s.id sid,
	s.`name` sname,
	c.`name` cname,
	sc.score 
FROM
	student s
	LEFT JOIN scores sc ON s.id = sc.s_id
	LEFT JOIN course c ON c.id = sc.c_id 
WHERE
	s.id = 1;

Mysql多表练习题30道_第1张图片

2.查询各个学科的平均成绩和最高成绩:

SELECT
	c.id,
	c.`name`,
	AVG( sc.score ),
	max( sc.score ) 
FROM
	course c
	LEFT JOIN scores sc ON c.id = sc.c_id 
GROUP BY
	c.id,
	c.`name`;

Mysql多表练习题30道_第2张图片

3.查询所有姓张的同学的各科成绩:

SELECT
	s.id,
	s.`name`,
	c.`name` cname,
	sc.score 
FROM
	student s
	LEFT JOIN scores sc ON sc.s_id = s.id
	LEFT JOIN course c ON c.id = sc.c_id 
WHERE
	s.`name` LIKE '张%';

Mysql多表练习题30道_第3张图片

4.查询每个同学的最高成绩和科目名称

SELECT
	t.id,
	t.NAME,
	c.id,
	c.NAME,
	r.score 
FROM
	(
	SELECT
		s.id,
		s.NAME,(
		SELECT
			max( score ) 
		FROM
			scores r 
		WHERE
			r.s_id = s.id 
		) score 
	FROM
		student s 
	) t
	LEFT JOIN scores r ON r.s_id = t.id 
	AND r.score = t.score
	LEFT JOIN course c ON r.c_id = c.id;

Mysql多表练习题30道_第4张图片

5.查询每个课程的最高分的学生信息

SELECT
	* 
FROM
	student s 
WHERE
	id IN (
	SELECT DISTINCT
		r.s_id 
	FROM
		(
		SELECT
			c.id,
			c.NAME,
			max( score ) score 
		FROM
			student s
			LEFT JOIN scores r ON r.s_id = s.id
			LEFT JOIN course c ON c.id = r.c_id 
		GROUP BY
			c.id,
			c.NAME 
		) t
		LEFT JOIN scores r ON r.c_id = t.id 
	AND t.score = r.score 
	);

Mysql多表练习题30道_第5张图片

6.查询名字中含有'张'或'李'字的学生的信息和各科成绩。

SELECT
	s.id,
	s.NAME sname,
	sc.score,
	c.NAME 
FROM
	student s
	LEFT JOIN scores sc ON s.id = sc.s_id
	LEFT JOIN course c ON sc.c_id = c.id 
WHERE
	s.NAME LIKE '%张%' 
	OR s.NAME LIKE '%李%';

Mysql多表练习题30道_第6张图片

7.查询平均成绩大于70的同学的信息。(子查询)

SELECT
	* 
FROM
	student 
WHERE
	id IN (
	SELECT
		sc.s_id 
	FROM
		scores sc 
	GROUP BY
		sc.s_id 
	HAVING
	avg( sc.score ) >= 70 
	);

Mysql多表练习题30道_第7张图片

8.将学生按照总分数进行排名。(从高到低)

SELECT
	s.id,
	s.NAME,
	sum( sc.score ) score 
FROM
	student s
	LEFT JOIN scores sc ON s.id = sc.s_id 
GROUP BY
	s.id,
	s.NAME 
ORDER BY
	score DESC,
	s.id ASC;

Mysql多表练习题30道_第8张图片

9.查询数学成绩的最高分、最低分、平均分。

SELECT
	c.NAME,
	max( sc.score ),
	min( sc.score ),
	avg( sc.score ) 
FROM
	course c
	LEFT JOIN scores sc ON c.id = sc.c_id 
WHERE
	c.NAME = '数学';

Mysql多表练习题30道_第9张图片

10.将各科目按照平均分排序。

SELECT
	c.id,
	c.NAME,
	avg( sc.score ) score 
FROM
	course c
	LEFT JOIN scores sc ON c.id = sc.c_id 
GROUP BY
	c.id,
	c.NAME 
ORDER BY
	score DESC;

Mysql多表练习题30道_第10张图片

11.查询老师的信息和他所带的科目的平均分

SELECT
	t.id,
	t.NAME,
	c.id cid,
	c.NAME cname,
	avg( r.score ) 
FROM
	teacher t
	LEFT JOIN course c ON t.id = c.t_id
	LEFT JOIN scores r ON r.c_id = c.id 
GROUP BY
	t.id,
	t.NAME,
	c.id,
	c.NAME;

Mysql多表练习题30道_第11张图片

12.查询被"Tom"和"Jerry"教的课程的最高分和最低分

SELECT
	t.id,
	t.NAME,
	c.id cid,
	c.NAME cname,
	max( r.score ),
	min( r.score ) 
FROM
	teacher t
	LEFT JOIN course c ON t.id = c.t_id
	LEFT JOIN scores r ON r.c_id = c.id 
GROUP BY
	t.id,
	t.NAME,
	c.id,
	c.NAME 
HAVING
	t.NAME IN ( 'Tom', 'Jerry' );

Mysql多表练习题30道_第12张图片

13.查询每个学生的最好成绩的科目名称(子查询)

SELECT
	t.id,
	t.sname,
	r.c_id,
	c.NAME,
	t.score 
FROM
	(
	SELECT
		s.id,
		s.NAME sname,
		max( r.score ) score 
	FROM
		student s
		LEFT JOIN scores r ON r.s_id = s.id 
	GROUP BY
		s.id,
		s.NAME 
	) t
	LEFT JOIN scores r ON r.s_id = t.id 
	AND r.score = t.score
	LEFT JOIN course c ON r.c_id = c.id;

 Mysql多表练习题30道_第13张图片

14.查询所有学生的课程及分数

SELECT
	s.id,
	s.NAME,
	c.id,
	c.NAME,
	r.score 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id
	LEFT JOIN course c ON c.id = r.c_id;

Mysql多表练习题30道_第14张图片

15.查询课程编号为1且课程成绩在60分以上的学生的学号和姓名(子查询)

SELECT
	s.*,
	r.* 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
WHERE
	r.c_id = 1 
	AND r.score > 60

Mysql多表练习题30道_第15张图片

16. 查询平均成绩大于等于70的所有学生学号、姓名和平均成绩

SELECT
	s.id,
	s.NAME,
	t.score 
FROM
	student s
	LEFT JOIN ( SELECT r.s_id, avg( r.score ) score FROM scores r GROUP BY r.s_id ) t ON s.id = t.s_id 
WHERE
	t.score >= 70;

Mysql多表练习题30道_第16张图片

17.查询有不及格课程的学生信息

SELECT
	* 
FROM
	student s 
WHERE
	id IN ( SELECT r.s_id FROM scores r GROUP BY r.s_id HAVING min( r.score ) < 60 );

Mysql多表练习题30道_第17张图片

18.查询每门课程有成绩的学生人数

SELECT
	c.id,
	c.NAME,
	count(*) 
FROM
	course c
	LEFT JOIN scores r ON c.id = r.c_id 
GROUP BY
	c.id,
	c.NAME;

Mysql多表练习题30道_第18张图片

19.查询每门课程的平均成绩,结果按照平均成绩降序排列,如果平均成绩相同,再按照课程编号升序排列

SELECT
	c.id,
	c.NAME,
	avg( score ) score 
FROM
	course c
	LEFT JOIN scores r ON c.id = r.c_id 
GROUP BY
	c.id,
	c.NAME 
ORDER BY
	score DESC,
	c.id ASC;

Mysql多表练习题30道_第19张图片

20.查询平均成绩大于60分的同学的学生编号和学生姓名和平均成绩

SELECT
	s.id,
	s.NAME sname,
	avg( r.score ) score 
FROM
	student s
	LEFT JOIN scores r ON r.s_id = s.id
	LEFT JOIN course c ON c.id = r.c_id 
GROUP BY
	s.id,
	s.NAME 
HAVING
	score > 65;

Mysql多表练习题30道_第20张图片

21.查询有且仅有一门课程成绩在80分以上的学生信息

SELECT
	s.id,
	s.NAME,
	s.gender 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
WHERE
	r.score > 80 
GROUP BY
	s.id,
	s.NAME,
	s.gender 
HAVING
	count(*) = 1;

Mysql多表练习题30道_第21张图片

22.查询出只有三门课程的学生的学号和姓名

SELECT
	s.id,
	s.NAME,
	s.gender 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
GROUP BY
	s.id,
	s.NAME,
	s.gender 
HAVING
	count(*) = 3;

Mysql多表练习题30道_第22张图片

23.查询有不及格课程的课程信息

SELECT
	* 
FROM
	course c 
WHERE
	id IN (
	SELECT
		r.c_id 
	FROM
		scores r 
	GROUP BY
		r.c_id 
	HAVING
	min( r.score ) < 60 
	);

Mysql多表练习题30道_第23张图片

24.查询至少选择4门课程的学生信息

SELECT
	s.id,
	s.NAME 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
GROUP BY
	s.id,
	s.NAME 
HAVING
	count(*) >= 4;

Mysql多表练习题30道_第24张图片

25.查询没有选全所有课程的同学的信息

SELECT
	* 
FROM
	student 
WHERE
	id IN (
	SELECT
		r.s_id 
	FROM
		scores r 
	GROUP BY
		r.s_id 
	HAVING
	count(*) != 5
	);

Mysql多表练习题30道_第25张图片

26.查询选全所有课程的同学的信息 

SELECT
	s.id,
	s.NAME,
	count(*) number 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
GROUP BY
	s.id,
	s.NAME 
HAVING
	number = ( SELECT count(*) FROM course );

Mysql多表练习题30道_第26张图片

27.查询各学生都选了多少门课

SELECT
	s.id,
	s.NAME,
	count(*) number 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id 
GROUP BY
	s.id,
	s.NAME;

Mysql多表练习题30道_第27张图片

28.查询课程名称为"java",且分数低于60分的学生姓名和分数

SELECT
	s.id,
	s.NAME,
	r.score 
FROM
	student s
	LEFT JOIN scores r ON s.id = r.s_id
	LEFT JOIN course c ON r.c_id = c.id 
WHERE
	c.NAME = 'java' 
	AND r.score < 60;

Mysql多表练习题30道_第28张图片

29.查询学过"Tony"老师授课的同学的信息

SELECT
	s.id,
	s.NAME 
FROM
	student s
	LEFT JOIN scores r ON r.s_id = s.id
	LEFT JOIN course c ON c.id = r.c_id
	LEFT JOIN teacher t ON t.id = c.t_id 
WHERE
	t.NAME = 'Tom';

Mysql多表练习题30道_第29张图片

30.查询没学过"Tony"老师授课的学生信息

SELECT
	* 
FROM
	student 
WHERE
	id NOT IN (
	SELECT DISTINCT
		s.id 
	FROM
		student s
		LEFT JOIN scores r ON r.s_id = s.id
		LEFT JOIN course c ON c.id = r.c_id
		LEFT JOIN teacher t ON t.id = c.t_id 
	WHERE
	t.NAME = 'Tom' 
	)

Mysql多表练习题30道_第30张图片 

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