系统初始以下脚本数据
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'); 7 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); -- 1、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) ); -- 2、查询student表的所有记录 SELECT * FROM student; -- 3、查询student表的第2条到4条记录 SELECT * from student LIMIT 1,2; -- 4、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; -- 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） SELECT * FROM student WHERE department in ('计算机系','英语系'); -- 6、从student表中查询年龄18~22岁的学生信息（用 BETWEEN AND） SELECT * FROM student WHERE YEAR(NOW()) - birth BETWEEN 18 and 22; -- 7、从student表中查询每个院系有多少人 SELECT department as '院系', count(*) as '人数' FROM student GROUP BY department; -- 8、从score表中查询每个科目的最高分 SELECT c_name,MAX(grade) as '最高分' FROM score GROUP BY c_name; -- 9、查询李四的考试科目（c_name）和考试成绩（grade） SELECT sc.c_name,sc.grade FROM student as s LEFT JOIN score as sc ON s.id = sc.stu_id WHERE s.`name`='李四'; -- 10、用连接的方式查询所有学生的信息和考试信息 SELECT * FROM student as s LEFT JOIN score as sc ON s.id = sc. stu_id; -- 11、计算每个学生的总成绩 SELECT s.name,SUM(sc.grade) as '总成绩' from student as s LEFT JOIN score as sc ON s.id = sc.stu_id GROUP BY s.name; -- 12、计算每个考试科目的平均成绩 SELECT sc.c_name,avg(grade) as '平均成绩' FROM score as sc GROUP BY sc.c_name; -- 13、查询计算机成绩低于95的学生信息 SELECT * FROM student as s LEFT JOIN score as sc on s.id=sc.stu_id WHERE c_name='计算机' AND grade < 95; -- 14、查询同时参加计算机和英语考试的学生的信息* SELECT * FROM student as s WHERE id in (SELECT stu_id from score as sc WHERE c_name = '计算机' OR c_name = '英语' GROUP BY stu_id HAVING COUNT(*) = 2); -- 二 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'); -- 15、将计算机考试成绩按从高到低进行排序 SELECT grade FROM score as sc WHERE c_name = '计算机' ORDER BY grade DESC; -- 16、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 as s UNION SELECT stu_id FROM score as sc ; -- 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 SELECT s.name,s.department,sc.c_name,sc.grade FROM student as s LEFT JOIN score as sc ON s.id = sc.stu_id WHERE s.name LIKE '%张%' OR s.name LIKE '%王%'; -- 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 SELECT s.name,s.birth,s.department,sc.c_name,sc.grade FROM student as s LEFT JOIN score as sc ON s.id = sc.stu_id WHERE s.address LIKE '湖南%';