MySQL——练习

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前期准备

/*
 数据导入：
 Navicat Premium Data Transfer

 Source Server         : localhost
 Source Server Type    : mysql
 Source Server Version : 50624
 Source Host           : localhost
 Source Database       : sqlexam

 Target Server Type    : MySQL
 Target Server Version : 50624
 File Encoding         : utf-8

 Date: 10/21/2016 06:46:46 AM
*/

SET NAMES utf8;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
--  Table structure for `class`
-- ----------------------------
DROP TABLE IF EXISTS `class`;
CREATE TABLE `class` (
  `cid` int(11) NOT NULL AUTO_INCREMENT,
  `caption` varchar(32) NOT NULL,
  PRIMARY KEY (`cid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `class`
-- ----------------------------
BEGIN;
INSERT INTO `class` VALUES (‘1‘, ‘三年二班‘), (‘2‘, ‘三年三班‘), (‘3‘, ‘一年二班‘), (‘4‘, ‘二年九班‘);
COMMIT;

-- ----------------------------
--  Table structure for `course`
-- ----------------------------
DROP TABLE IF EXISTS `course`;
CREATE TABLE `course` (
  `cid` int(11) NOT NULL AUTO_INCREMENT,
  `cname` varchar(32) NOT NULL,
  `teacher_id` int(11) NOT NULL,
  PRIMARY KEY (`cid`),
  KEY `fk_course_teacher` (`teacher_id`),
  CONSTRAINT `fk_course_teacher` FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`tid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `course`
-- ----------------------------
BEGIN;
INSERT INTO `course` VALUES (‘1‘, ‘生物‘, ‘1‘), (‘2‘, ‘物理‘, ‘2‘), (‘3‘, ‘体育‘, ‘3‘), (‘4‘, ‘美术‘, ‘2‘);
COMMIT;

-- ----------------------------
--  Table structure for `score`
-- ----------------------------
DROP TABLE IF EXISTS `score`;
CREATE TABLE `score` (
  `sid` int(11) NOT NULL AUTO_INCREMENT,
  `student_id` int(11) NOT NULL,
  `course_id` int(11) NOT NULL,
  `num` int(11) NOT NULL,
  PRIMARY KEY (`sid`),
  KEY `fk_score_student` (`student_id`),
  KEY `fk_score_course` (`course_id`),
  CONSTRAINT `fk_score_course` FOREIGN KEY (`course_id`) REFERENCES `course` (`cid`),
  CONSTRAINT `fk_score_student` FOREIGN KEY (`student_id`) REFERENCES `student` (`sid`)
) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `score`
-- ----------------------------
BEGIN;
INSERT INTO `score` VALUES (‘1‘, ‘1‘, ‘1‘, ‘10‘), (‘2‘, ‘1‘, ‘2‘, ‘9‘), (‘5‘, ‘1‘, ‘4‘, ‘66‘), (‘6‘, ‘2‘, ‘1‘, ‘8‘), (‘8‘, ‘2‘, ‘3‘, ‘68‘), (‘9‘, ‘2‘, ‘4‘, ‘99‘), (‘10‘, ‘3‘, ‘1‘, ‘77‘), (‘11‘, ‘3‘, ‘2‘, ‘66‘), (‘12‘, ‘3‘, ‘3‘, ‘87‘), (‘13‘, ‘3‘, ‘4‘, ‘99‘), (‘14‘, ‘4‘, ‘1‘, ‘79‘), (‘15‘, ‘4‘, ‘2‘, ‘11‘), (‘16‘, ‘4‘, ‘3‘, ‘67‘), (‘17‘, ‘4‘, ‘4‘, ‘100‘), (‘18‘, ‘5‘, ‘1‘, ‘79‘), (‘19‘, ‘5‘, ‘2‘, ‘11‘), (‘20‘, ‘5‘, ‘3‘, ‘67‘), (‘21‘, ‘5‘, ‘4‘, ‘100‘), (‘22‘, ‘6‘, ‘1‘, ‘9‘), (‘23‘, ‘6‘, ‘2‘, ‘100‘), (‘24‘, ‘6‘, ‘3‘, ‘67‘), (‘25‘, ‘6‘, ‘4‘, ‘100‘), (‘26‘, ‘7‘, ‘1‘, ‘9‘), (‘27‘, ‘7‘, ‘2‘, ‘100‘), (‘28‘, ‘7‘, ‘3‘, ‘67‘), (‘29‘, ‘7‘, ‘4‘, ‘88‘), (‘30‘, ‘8‘, ‘1‘, ‘9‘), (‘31‘, ‘8‘, ‘2‘, ‘100‘), (‘32‘, ‘8‘, ‘3‘, ‘67‘), (‘33‘, ‘8‘, ‘4‘, ‘88‘), (‘34‘, ‘9‘, ‘1‘, ‘91‘), (‘35‘, ‘9‘, ‘2‘, ‘88‘), (‘36‘, ‘9‘, ‘3‘, ‘67‘), (‘37‘, ‘9‘, ‘4‘, ‘22‘), (‘38‘, ‘10‘, ‘1‘, ‘90‘), (‘39‘, ‘10‘, ‘2‘, ‘77‘), (‘40‘, ‘10‘, ‘3‘, ‘43‘), (‘41‘, ‘10‘, ‘4‘, ‘87‘), (‘42‘, ‘11‘, ‘1‘, ‘90‘), (‘43‘, ‘11‘, ‘2‘, ‘77‘), (‘44‘, ‘11‘, ‘3‘, ‘43‘), (‘45‘, ‘11‘, ‘4‘, ‘87‘), (‘46‘, ‘12‘, ‘1‘, ‘90‘), (‘47‘, ‘12‘, ‘2‘, ‘77‘), (‘48‘, ‘12‘, ‘3‘, ‘43‘), (‘49‘, ‘12‘, ‘4‘, ‘87‘), (‘52‘, ‘13‘, ‘3‘, ‘87‘);
COMMIT;

-- ----------------------------
--  Table structure for `student`
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `sid` int(11) NOT NULL AUTO_INCREMENT,
  `gender` char(1) NOT NULL,
  `class_id` int(11) NOT NULL,
  `sname` varchar(32) NOT NULL,
  PRIMARY KEY (`sid`),
  KEY `fk_class` (`class_id`),
  CONSTRAINT `fk_class` FOREIGN KEY (`class_id`) REFERENCES `class` (`cid`)
) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `student`
-- ----------------------------
BEGIN;
INSERT INTO `student` VALUES (‘1‘, ‘男‘, ‘1‘, ‘理解‘), (‘2‘, ‘女‘, ‘1‘, ‘钢蛋‘), (‘3‘, ‘男‘, ‘1‘, ‘张三‘), (‘4‘, ‘男‘, ‘1‘, ‘张一‘), (‘5‘, ‘女‘, ‘1‘, ‘张二‘), (‘6‘, ‘男‘, ‘1‘, ‘张四‘), (‘7‘, ‘女‘, ‘2‘, ‘铁锤‘), (‘8‘, ‘男‘, ‘2‘, ‘李三‘), (‘9‘, ‘男‘, ‘2‘, ‘李一‘), (‘10‘, ‘女‘, ‘2‘, ‘李二‘), (‘11‘, ‘男‘, ‘2‘, ‘李四‘), (‘12‘, ‘女‘, ‘3‘, ‘如花‘), (‘13‘, ‘男‘, ‘3‘, ‘刘三‘), (‘14‘, ‘男‘, ‘3‘, ‘刘一‘), (‘15‘, ‘女‘, ‘3‘, ‘刘二‘), (‘16‘, ‘男‘, ‘3‘, ‘刘四‘);
COMMIT;

-- ----------------------------
--  Table structure for `teacher`
-- ----------------------------
DROP TABLE IF EXISTS `teacher`;
CREATE TABLE `teacher` (
  `tid` int(11) NOT NULL AUTO_INCREMENT,
  `tname` varchar(32) NOT NULL,
  PRIMARY KEY (`tid`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `teacher`
-- ----------------------------
BEGIN;
INSERT INTO `teacher` VALUES (‘1‘, ‘张磊老师‘), (‘2‘, ‘李平老师‘), (‘3‘, ‘刘海燕老师‘), (‘4‘, ‘朱云海老师‘), (‘5‘, ‘李杰老师‘);
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

练习

# 1、查询所有的课程的名称以及对应的任课老师姓名
SELECT
	course.cname,
	teacher.tname 
FROM
	course
	INNER JOIN teacher ON course.teacher_id = teacher.tid;
	
# 2、查询学生表中男女生各有多少人
SELECT
	gender,
	count( sid ) 
FROM
	student 
GROUP BY
	gender;
	
# 3、查询物理成绩等于100的学生的姓名
SELECT
	student.sname 
FROM
	student
	INNER JOIN score ON student.sid = score.student_id
	INNER JOIN course ON score.course_id = course.cid 
WHERE
	course.cname = ‘物理‘ 
	AND score.num = 100;

# 4、查询平均成绩大于八十分的同学的姓名和平均成绩
SELECT
	student.sname,
	avg( score.num ) 
FROM
	student
	INNER JOIN score ON student.sid = score.student_id 
GROUP BY
	score.student_id 
HAVING
	avg( score.num )> 80;

# 5、查询所有学生的学号，姓名，选课数，总成绩
SELECT
	student_id,
	student.sname,
	count( course_id ) AS course_num,
	sum( num ) AS total_score 
FROM
	score
	INNER JOIN student ON score.student_id = student.sid 
GROUP BY
	student_id;


# 6、 查询姓李老师的个数
SELECT
	count( tid ) 
FROM
	teacher 
WHERE
	tname LIKE ‘李%‘;

# 7、 查询没有报李平老师课的学生姓名
SELECT
	sname 
FROM
	student 
WHERE
	sid NOT IN (
	SELECT DISTINCT
		score.student_id 
	FROM
		score
	WHERE
		course_id IN (
			SELECT
				course.cid 
			FROM
				teacher
				INNER JOIN course ON teacher.tid = course.teacher_id 
			WHERE
				teacher.tname = ‘李平老师‘
		)
	);

# 8、 查询物理课程比生物课程高的学生的学号
SELECT
	t1.student_id 
FROM
	(
	SELECT
		student_id,
		num 
	FROM
		score
		INNER JOIN course ON score.course_id = course.cid 
	WHERE
		course.cname = ‘物理‘
	) AS t1
	INNER JOIN 
	(
	SELECT
		student_id,
		num 
	FROM
		score
		INNER JOIN course ON score.course_id = course.cid 
	WHERE
		course.cname = ‘生物‘
	) AS t2 
	ON t1.student_id = t2.student_id 
WHERE
	t1.num > t2.num;

# 9、 查询没有同时选修物理课程和体育课程的学生姓名
SELECT
	sname 
FROM
	student 
WHERE
	sid 
	NOT IN 
	(
	SELECT DISTINCT
		student_id 
	FROM
		score 
	WHERE
		course_id IN ( SELECT cid FROM course WHERE cname IN ( ‘物理‘, ‘体育‘ ) ) 
	GROUP BY
		student_id 
	HAVING
		COUNT( course_id )= 2
	);

# 10、查询挂科超过两门(包括两门)的学生姓名和班级
SELECT
	sname,
	class.caption 
FROM
	student
	INNER JOIN class ON student.class_id = class.cid 
WHERE
	sid IN ( 
	SELECT
		student_id 
	FROM
		score 
	WHERE
		num < 60 
	GROUP BY
		student_id 
	HAVING
		COUNT( num )>= 2
);

# 11、查询选修了所有课程的学生姓名
SELECT
	student.sname
FROM
	score INNER JOIN student ON score.student_id=student.sid
GROUP BY
	student_id
HAVING 
	COUNT( course_id )=( SELECT COUNT( cid ) FROM course )
;

# 12、查询李平老师教的课程的所有成绩记录
SELECT
	num 
FROM
	score
	INNER JOIN course ON score.course_id = course.cid
	INNER JOIN teacher ON course.teacher_id = teacher.tid 
WHERE
	teacher.tname = ‘李平老师‘;

# 13、查询全部学生都选修了的课程号和课程名
SELECT 
	course_id,
	course.cname
FROM 
	score 
	INNER JOIN 
	course 
	ON 
	score.course_id=course.cid
GROUP BY 
	course_id 
HAVING 
	count( student_id )=( 
		SELECT 
			count( sid ) 
		FROM 
			student 
	);

# 14、查询每门课程被选修的次数
SELECT
	course_id,
	COUNT( student_id ) 
FROM
	score 
GROUP BY
	course_id;

# 15、查询之选修了一门课程的学生姓名和学号
SELECT
	student_id,
	student.sname 
FROM
	score
	INNER JOIN student ON score.student_id = student.sid 
GROUP BY
	student_id 
HAVING
	COUNT( course_id )= 1;

# 16、查询所有学生考出的成绩并按从高到低排序（成绩去重）
SELECT DISTINCT
	num 
FROM
	score 
ORDER BY
	num DESC;

# 17、查询平均成绩大于85的学生姓名和平均成绩
SELECT
	student.sname,
	avg( num ) 
FROM
	score
	INNER JOIN student ON score.student_id = student.sid 
GROUP BY
	student_id 
HAVING
	avg( num )> 85;

# 18、查询生物成绩不及格的学生姓名和对应生物分数
SELECT
	student.sname,
	num 
FROM
	score
	INNER JOIN student ON score.student_id = student.sid 
WHERE
	course_id IN ( SELECT cid FROM course WHERE cname = ‘生物‘ ) 
	AND num < 60;

# 19、查询在所有选修了李平老师课程的学生中，这些课程(李平老师的课程，不是所有课程)平均成绩最高的学生姓名
SELECT
	student.sname
FROM
	score 
	INNER JOIN 
	student 
	ON
	score.student_id=student.sid
WHERE
	course_id IN ( 
		SELECT 
		cid 
		FROM 
		course 
		INNER JOIN 
		teacher 
		ON 
		course.teacher_id = teacher.tid 
		WHERE 
		teacher.tname = ‘李平老师‘
	) 
GROUP BY
	student_id
ORDER BY
	avg(num) DESC
	LIMIT 1;

# 20、查询每门课程成绩最好的前两名学生姓名


# 21、查询不同课程但成绩相同的学号，课程号，成绩


# 22、查询没学过“叶平”老师课程的学生姓名以及选修的课程名称；


# 23、查询所有选修了学号为1的同学选修过的一门或者多门课程的同学学号和姓名；


# 24、任课最多的老师中学生单科成绩最高的学生姓名

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