文章标题

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);
– 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
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
SELECT id,name,sex,2013-birth AS age,department
FROM student
WHERE 2013-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 c_name, grade
FROM score WHERE stu_id=
(SELECT id FROM student
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 student.id,name,sex,birth,department,c_name,grade
FROM student,score
WHERE student.id=score.stu_id;
– 计算每个学生的总成绩
SELECT student.id,name,SUM(grade) FROM student,score
WHERE student.id=score.stu_id
GROUP BY id;
– 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);
– 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 =ANY
( 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’ );
SELECT a.* FROM student a ,score b ,score c
WHERE a.id=b.stu_id
AND b.c_name=’计算机’
AND a.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 stu_id, grade
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;