表查询之综合练习
综合练习
练习准备工作
init.sql文件内容
/*
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;
从init.sql文件中导入数据
#准备表、记录
mysql> create database db1;
mysql> use db1;
mysql> source W:\MYSQL\mysql-5.6.47-winx64\init.sql; -- source 后面接sql文件的绝对路径
查看存在的表
mysql> show tables;
+---------------+
| Tables_in_db3 |
+---------------+
| class |
| course |
| score |
| student |
| teacher |
+---------------+
表内容
mysql> select * from class;
+-----+--------------+
| cid | caption |
+-----+--------------+
| 1 | 三年二班 |
| 2 | 三年三班 |
| 3 | 一年二班 |
| 4 | 二年九班 |
+-----+--------------+
4 rows in set (0.00 sec)
mysql> select * from course;
+-----+--------+------------+
| cid | cname | teacher_id |
+-----+--------+------------+
| 1 | 生物 | 1 |
| 2 | 物理 | 2 |
| 3 | 体育 | 3 |
| 4 | 美术 | 2 |
+-----+--------+------------+
4 rows in set (0.00 sec)
mysql> select * from score;
+-----+------------+-----------+-----+
| sid | student_id | course_id | num |
+-----+------------+-----------+-----+
| 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 |
+-----+------------+-----------+-----+
47 rows in set (0.00 sec)
mysql> select * from student;
+-----+--------+----------+--------+
| sid | gender | class_id | sname |
+-----+--------+----------+--------+
| 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 |
+-----+--------+----------+--------+
16 rows in set (0.00 sec)
mysql> select * from teacher;
+-----+-----------------+
| tid | tname |
+-----+-----------------+
| 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 |
+-----+-----------------+
5 rows in set (0.00 sec)
练习集
1、查询所有的课程的名称以及对应的任课老师姓名
SELECT
c.cname,
t.tname
FROM
course AS c
INNER JOIN teacher AS t ON c.teacher_id = t.tid;
2、查询学生表中男女生各有多少人
SELECT
gender,
count(gender)
FROM
student
GROUP BY
gender;
3、查询物理成绩等于100的学生的姓名
SELECT
st.sname
FROM
student AS st
WHERE
sid IN (
SELECT
student_id
FROM
score sc
INNER JOIN course c ON sc.course_id = c.cid
WHERE
c.cname = "物理"
AND sc.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
st.sname,
avg(num)
FROM
student AS st
INNER JOIN score AS sc ON st.sid = sc.student_id
GROUP BY
sc.student_id
HAVING
avg(num) > 80;
5、查询所有学生的学号，姓名，选课数，总成绩
SELECT
st.sid,
st.sname,
count(course_id),
sum(num)
FROM
student AS st
INNER JOIN score AS sc ON st.sid = sc.student_id
GROUP BY
sc.student_id;
SELECT
st.sid,
st.sname,
sc.cc,
sc.sn
FROM
student AS st
LEFT JOIN (
SELECT
student_id,
count(course_id) cc,
sum(num) sn
FROM
score
GROUP BY
student_id
) sc ON st.sid = sc.student_id;
6、 查询姓李老师的个数
SELECT
count(tname)
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
student_id
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
teacher_id = (
SELECT
tid
FROM
teacher
WHERE
tname = "李平老师"
)
)
);
8、 查询物理课程比生物课程高的学生的学号
# 先拿到选择了生物和物理俩个课程的学生id
# 再拿到该学生的生物成绩 和 物理成绩
# 再进行比较,物理成绩比生物成绩高的过滤出来
# 最后返回该学生的id
SELECT
t1.student_id
FROM
(
SELECT
student_id,
num AS snum
FROM
score
WHERE
course_id = (
SELECT
cid
FROM
course
WHERE
cname = "生物"
)
) AS t1
INNER JOIN (
SELECT
student_id,
num AS wnum
FROM
score
WHERE
course_id = (
SELECT
cid
FROM
course
WHERE
cname = "物理"
)
) AS t2 ON t2.student_id = t1.student_id
WHERE
t1.snum < t2.wnum;
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 IN (
SELECT
student_id
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
cname = "物理"
OR cname = "体育"
)
GROUP BY
student_id
HAVING
count(course_id) = 1
)
OR sid NOT IN (SELECT student_id FROM score);
10、查询挂科超过两门(包括两门)的学生姓名和班级
SELECT
st.sname,
c.caption
FROM
student AS st
INNER JOIN class AS c ON st.class_id = c.cid
INNER JOIN (
SELECT
student_id
FROM
score
WHERE
num < 60
HAVING
count(student_id) >= 2
) AS t1 ON t1.student_id = st.sid;
11 、查询选修了所有课程的学生姓名
SELECT
sname
FROM
student
WHERE
sid IN (
SELECT
student_id
FROM
score
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
*
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
teacher_id = (
SELECT
tid
FROM
teacher
WHERE
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
cid,
cname
FROM
course
WHERE
cid = ALL (
SELECT
course_id
FROM
score
GROUP BY
student_id
);
14、查询每门课程被选修的次数
SELECT
count(course_id)
FROM
score
GROUP BY
course_id;
15、查询只选修了一门课程的学生姓名和学号
SELECT
sname,
sid
FROM
student
WHERE
sid IN (
SELECT
student_id
FROM
score
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
st.sname,
avg(num)
FROM
student AS st
INNER JOIN score AS sc ON st.sid = sc.student_id
GROUP BY
sc.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
st.sname,
sc.num
FROM
student AS st
INNER JOIN (
SELECT
*
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
cname = "生物"
)
) AS sc ON st.sid = sc.student_id
WHERE
sc.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
st.sname
FROM
student AS st
INNER JOIN (
SELECT
*
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
teacher_id IN (
SELECT
tid
FROM
teacher
WHERE
tname = "李平老师"
)
)
) AS sc ON st.sid = sc.student_id
GROUP BY
st.sid
ORDER BY
avg(num) DESC
LIMIT 1;
20、查询每门课程成绩最好的前两名s学生姓名(!!!)
SELECT
sname
FROM
student
WHERE
sid IN (
SELECT
student_id
FROM
score sco
INNER JOIN (
SELECT
sc.sid ss
FROM
score sc
LEFT JOIN (
SELECT
sid,
(
SELECT
num
FROM
score AS s2
WHERE
s2.course_id = s1.course_id
ORDER BY
num DESC
LIMIT 0,
1
) AS first_num,
(
SELECT
num
FROM
score AS s2
WHERE
s2.course_id = s1.course_id
ORDER BY
num DESC
LIMIT 1,
1
) AS second_num
FROM
score AS s1
) AS t1 ON sc.sid = t1.sid
WHERE
sc.num <= t1.first_num
AND sc.num >= t1.second_num
) AS t1 ON t1.ss = sco.sid
);
21、查询不同课程但成绩相同的学号，课程号，成绩
SELECT DISTINCT
sc1.student_id,
sc2.student_id,
sc1.course_id,
sc2.course_id,
sc1.num
FROM
score AS sc1
INNER JOIN score AS sc2 ON sc1.num = sc2.num
AND sc1.course_id != sc2.course_id;
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； 1 3
SELECT
t2.ts,
co.cname
FROM
course AS co
RIGHT JOIN (
SELECT
t1.sname AS ts,
sc1.course_id AS sco
FROM
score AS sc1
RIGHT JOIN (
SELECT
sname,
sid
FROM
student
WHERE
sid NOT IN (
SELECT DISTINCT
student_id
FROM
score
WHERE
score.course_id IN (
SELECT
cid
FROM
course
INNER JOIN teacher ON course.teacher_id = teacher.tid
WHERE
tname = '李平老师'
)
)
) AS t1 ON t1.sid = sc1.student_id
) AS t2 ON t2.sco = co.cid;
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个选修课程的个数；
SELECT
student_id,
sname,
count(course_id)
FROM
score
LEFT JOIN student ON score.student_id = student.sid
WHERE
student_id != 1
AND course_id IN (
SELECT
course_id
FROM
score
WHERE
student_id = 1
)
GROUP BY
student_id;
24、任课最多的老师中学生单科成绩最高的学生姓名
SELECT
sname
FROM
student
WHERE
sid = (
SELECT
student_id
FROM
score
WHERE
course_id IN (
SELECT
cid
FROM
course
WHERE
teacher_id = (
SELECT
teacher_id
FROM
course
GROUP BY
teacher_id
ORDER BY
count(teacher_id) DESC
LIMIT 1
)
)
ORDER BY
num DESC
LIMIT 1
);
