2018-03-02 周测试题
系统初始了以下脚本数据
- 向student表插入记录的INSERT语句如下：
INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');
INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');
INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');
- 向score表插入记录的INSERT语句如下：
INSERT INTO score VALUES(NULL,901, '计算机',98);
INSERT INTO score VALUES(NULL,901, '英语', 80);
INSERT INTO score VALUES(NULL,902, '计算机',65);
INSERT INTO score VALUES(NULL,902, '中文',88);
INSERT INTO score VALUES(NULL,903, '中文',95);
INSERT INTO score VALUES(NULL,904, '计算机',70);
INSERT INTO score VALUES(NULL,904, '英语',92);
INSERT INTO score VALUES(NULL,905, '英语',94);
INSERT INTO score VALUES(NULL,906, '计算机',90);
INSERT INTO score VALUES(NULL,906, '英语',85);
试题
1、创建student和score表语句
2、查询student表的所有记录
3、查询student表的第2条到4条记录
4、从student表查询所有学生的学号（id）、姓名（name）和院系（department）的信息
5、从student表中查询计算机系和英语系的学生的信息（用 IN 关键字）
6、从student表中查询年龄18~22岁的学生信息（用 BETWEEN AND）
7、从student表中查询每个院系有多少人
8、从score表中查询每个科目的最高分
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9、查询李四的考试科目（c_name）和考试成绩（grade）
10、用连接的方式查询所有学生的信息和考试信息
11、计算每个学生的总成绩
12、计算每个考试科目的平均成绩
13、查询计算机成绩低于95的学生信息
14、查询同时参加计算机和英语考试的学生的信息
15、将计算机考试成绩按从高到低进行排序
16、从student表和score表中查询出学生的学号，然后合并查询结果
17、查询姓张或者姓王的同学的姓名、院系和考试科目及成绩
18、查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩
-- 创建student和score表语句
CREATE TABLE student(id INT(10) PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
sex VARCHAR(4),
birth YEAR,
department VARCHAR(20) NOT NULL,
address VARCHAR(50)
);
CREATE TABLE score(
id INT(10) PRIMARY KEY AUTO_INCREMENT,
stu_id INT(10) NOT NULL,
c_name VARCHAR(20),
grade INT(10)
);
-- 查询student表的所有记录
SELECT * FROM student;
-- 查询student表的第2条到4条记录
SELECT * FROM student LIMIT 1,3;
-- 从student表查询所有学生的学号（id）、姓名（name）和院系（department）的信息
SELECT id,name,department
FROM student ;
-- 从student表中查询计算机系和英语系的学生的信息（用 IN 关键字）
SELECT * FROM student
WHERE department in('计算机系','英语系');
-- 从student表中查询年龄18~22岁的学生信息（用 BETWEEN AND）
SELECT id,name,sex,2018-birth AS age,department,address
FROM student
WHERE 2018-birth
BETWEEN 18 AND 22;
-- 从student表中查询每个院系有多少人
SELECT department,COUNT(id)
FROM student
GROUP BY department;
-- 从score表中查询每个科目的最高分
SELECT c_name,MAX(grade)
FROM score
GROUP BY c_name;
-- 查询李四的考试科目（c_name）和考试成绩（grade）
-- SELECT id FROM student WHERE name in ('李四')
SELECT c_name,grade
FROM score
WHERE stu_id = (SELECT id FROM student WHERE name = '李四');
SELECT name AS '姓名',c_name AS '课程名称',grade AS '课程分数'
FROM score AS c LEFT JOIN student AS s ON stu_id =s. id
WHERE name = '李四';
-- 用连接的方式查询所有学生的信息和考试信息
SELECT *
FROM student,score
WHERE student.id=score.stu_id;
SELECT * FROM score AS c LEFT JOIN student AS s ON c.stu_id = s.id;
-- 计算每个学生的总成绩
SELECT student.id,name AS '姓名',SUM(grade) AS '总成绩'
FROM student,score
GROUP BY id;
SELECT s.name AS '姓名',SUM(c.grade) AS '总成绩' FROM score AS c
LEFT JOIN student AS s ON c.stu_id = s.id GROUP BY s.name;
-- 计算每个考试科目的平均成绩
SELECT c_name,AVG(grade)
FROM score
GROUP BY c_name;
-- 查询计算机成绩低于95的学生信息
SELECT * FROM student
WHERE id in (SELECT stu_id FROM score WHERE c_name='计算机' AND grade<95);
-- 第一种
SELECT s.* FROM score AS c LEFT JOIN student AS s ON c.stu_id = s.id
WHERE c.c_name = '计算机' AND c.grade < 95;
-- 第二种
SELECT * FROM student WHERE id IN (SELECT stu_id FROM score WHERE c_name = '计算机'
-- 查询同时参加计算机和英语考试的学生的信息
SELECT * FROM student
WHERE id in
(SELECT stu_id FROM score WHERE stu_id in (SELECT stu_id FROM score WHERE c_name='计算机')
AND c_name='英语');
-- 第一种
SELECT * FROM student WHERE id IN
(SELECT stu_id FROM score
WHERE c_name = '计算机' OR c_name = '英语'
GROUP BY stu_id HAVING COUNT(*) = 2);
-- 第二种
SELECT * FROM student WHERE id IN
(SELECT stu_id FROM score WHERE stu_id
IN(SELECT stu_id FROM score WHERE c_name = '计算机') AND c_name = '英语');
-- 第三种
SELECT s.* FROM student AS s, score AS b ,score AS c
WHERE s.id = b.stu_id AND b.c_name = '计算机' AND s.id = c.stu_id AND c.c_name = '英语';
-- 将计算机考试成绩按从高到低进行排序
SELECT c_name,grade FROM score
WHERE c_name='计算机'
ORDER BY grade DESC;
SELECT grade AS '计算机考试成绩' FROM score
WHERE c_name = '计算机' ORDER BY grade DESC;
-- 从student表和score表中查询出学生的学号，然后合并查询结果
SELECT id FROM student
UNION
SELECT stu_id FROM score;
SELECT id AS '学号' FROM student
UNION
SELECT DISTINCT stu_id AS '学号' FROM score;
-- 查询姓张或者姓王的同学的姓名、院系和考试科目及成绩
SELECT name,department,c_name,grade
FROM student,score
WHERE (name LIKE '张%' OR name LIKE'王%')
AND student.id=score.stu_id;
SELECT s.name AS '姓名',s.department AS '院系',c.c_name AS '考试科目',c.grade AS '成绩'
FROM score AS c LEFT JOIN student AS s ON c.stu_id = s.id
WHERE s.name LIKE '张%' OR s.name LIKE '王%';
-- 查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩
SELECT name,2018-birth AS age,department,address, c_name,grade
FROM student,score
WHERE address LIKE '湖南%'
AND student.id=score.stu_id;
SELECT s.name AS '姓名',YEAR(NOW())-s.birth AS '年龄',s.department AS '院系',c.c_name AS '考试科目',c.grade AS '成绩'
FROM score AS c LEFT JOIN student AS s ON c.stu_id = s.id
WHERE s.address LIKE '湖南%';