# 创建数据库school
CREATE DATABASE school;
# 创建表student
DROP TABLE IF EXISTS student;
CREATE TABLE student(
`s_id` TINYINT(3) UNSIGNED NOT NULL AUTO_INCREMENT comment '学生编号' ,
`s_name` VARCHAR(4) NOT NULL comment '学生姓名',
`s_sex` VARCHAR(2) NOT NULL comment '学生性别',
`s_birthday` DATETIME comment '学生生日',
`class` VARCHAR(5) comment '学生班级',
PRIMARY KEY(`s_id`),
KEY s_name(`s_name`)
)engine=innodb DEFAULT CHARSET=utf8 comment '学生表';
# 创建表course
CREATE TABLE course(
c_id VARCHAR(5) NOT NULL comment '课程编号',
c_name VARCHAR(10) NOT NULL comment '课程名称',
t_id VARCHAR(10) NOT NULL comment '授课老师'
)engine=innodb DEFAULT CHARSET=utf8 comment '课程表';
# 创建表score
CREATE TABLE score (
s_id VARCHAR(3) NOT NULL comment '学生编号',
c_id VARCHAR(5) NOT NULL comment '课程编号',
degree NUMERIC(10, 1) NOT NULL comment '学分'
)engine=innodb DEFAULT CHARSET=utf8 comment '分数表';
# 创建表teacher
CREATE TABLE teacher (
t_id VARCHAR(3) NOT NULL comment '教师编号',
t_name VARCHAR(4) NOT NULL comment '教师名称',
t_sex VARCHAR(2) NOT NULL comment '教师性别',
t_birthday DATETIME NOT NULL comment '教师生日',
prof VARCHAR(6) comment '职称',
depart VARCHAR(10) NOT NULL comment '院系'
)engine=innodb DEFAULT CHARSET=utf8 comment '教师表';
# 向各表导入数据
INSERT INTO student (s_id,s_name,s_sex,s_birthday,class) VALUES
(108 ,'曾华' ,'男' ,'1977-09-01',95033),
(105 ,'匡明' ,'男' ,'1975-10-02',95031),
(107 ,'王丽' ,'女' ,'1976-01-23',95033),
(101 ,'李军' ,'男' ,'1976-02-20',95033),
(109 ,'王芳' ,'女' ,'1975-02-10',95031),
(103 ,'陆君' ,'男' ,'1974-06-03',95031);
INSERT INTO course(c_id,c_name,t_id) VALUES
('3-105' ,'计算机导论',825),
('3-245' ,'操作系统' ,804),
('6-166' ,'数据电路' ,856),
('9-888' ,'高等数学' ,100);
INSERT INTO score(s_id,c_id,degree) VALUES
(103,'3-245',86),
(105,'3-245',75),
(109,'3-245',68),
(103,'3-105',92),
(105,'3-105',88),
(109,'3-105',76),
(101,'3-105',64),
(107,'3-105',91),
(108,'3-105',78),
(101,'6-166',85),
(107,'6-106',79),
(108,'6-166',81);
INSERT INTO teacher(t_id,t_name,t_sex,t_birthday,prof,depart) VALUES
(804,'李诚','男','1958-12-02','副教授','计算机系'),
(856,'张旭','男','1969-03-12','讲师','电子工程系'),
(825,'王萍','女','1972-05-05','助教','计算机系'),
(831,'刘冰','女','1977-08-14','助教','电子工程系');
#sql题目(基础)
1、 查询student表中的所有记录的s_name、s_sex和class列。
#无别名
select s_name,s_sex,class from student;
#有别名
select s_name as 学生姓名, s_sex as 学生性别, class as 学生班级 from student;
2、 查询教师所有的单位即不重复的depart列。
select distinct depart from teacher;
3、 查询student表的所有记录。
select * from student;
4、 查询score表中成绩在60到80之间的所有记录。
select * from score where degree>=60 and degree<=80;
5、 查询score表中成绩为85，86或88的记录。
#方法1
select * from score where degree=85 or degree=86 or degree=88;
#方法2
select * from score where degree in (85,86,88);
6、 查询student表中“95031”班或性别为“女”的同学记录。
select * from student where class=95031 or s_sex='女';
7、 以class降序查询student表的所有记录。
select * from student order by class desc;
8、 以c_id升序、degree降序查询score表的所有记录。
select * from score order by c_id asc,degree desc;
9、 查询“95031”班的学生人数。
select count(*) as 95031班学生人数 from student where class=95031;
10、查询score表中的最高分的学生学号和课程号。
select s_id,c_id from score where degree=(select MAX(degree) from score);
11、查询‘3-105’号课程的平均分。
select AVG(degree) from score where c_id='3-105';
12、查询score表中至少有5名学生选修的并以3开头的课程的平均分数。
select AVG(degree) as 平均分,c_id as 课程 from score where c_id like '3%' group by c_id having count(s_id)>=5;
13、查询最低分大于70，最高分小于90的s_id列。
select s_id from score where degree>70 and degree <90;
14、查询所有学生的s_name、c_id和degree列。
select student.s_name,score.c_id,score.degree from student left join score on student.s_id=score.s_id;
15、查询所有学生的s_id、c_name和degree列。
select student.s_id,course.c_name,score.degree from student
join score on student.s_id=score.s_id
left join course on score.c_id=course.c_id;
16、查询所有学生的s_name、c_name和degree列。
select student.s_name,course.c_name,score.degree from student
join score on student.s_id=score.s_id
left join course on score.c_id=course.c_id;
17、查询“95033”班所选课程的平均分。
select AVG(degree) from score
join student on score.s_id=student.s_id where class=95033;
18、假设使用如下命令建立了一个grade表：
create table grade(
low varchar(3) not null comment 'low',
upp varchar(3) not null comment 'upp',
rank varchar(3) not null comment 'rank'
)engine=innodb DEFAULT CHARSET=utf8 comment '等级表';
insert into grade values(90,100,'A');
insert into grade values(80,89,'B');
insert into grade values(70,79,'C');
insert into grade values(60,69,'D');
insert into grade values(0,59,'E');
现查询所有同学的s_id、c_id和rank列?
select score.s_id,score.c_id,grade.rank from score,grade
where score.degree>=grade.low and score.degree<=grade.upp;
19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
#**all的意思是“对于子查询返回的列中的所有值，如果比较结果为true，则返回true”
select * from score where c_id='3-105' and degree>all(select degree from score where s_id=109 and c_id='3-105');
20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
select * from score group by degree having count(c_id)>1;
select * from score
where degree not in
(select MAX(degree) from score group by s_id)
and s_id in
(select s_id from score group by s_id having count(s_id)>1);
21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select * from score
where degree>(select degree from score where s_id=109 and c_id='3-105');
22、查询和学号为108的同学同年出生的所有学生的s_id、s_name和s_birthday列。
select s_id,s_name,s_birthday from student
where YEAR(s_birthday)=(select YEAR(s_birthday) from student where s_id=108);
23、查询“张旭“教师任课的学生成绩。
#方法1
select s.s_id,s.degree from score s
join course c on s.c_id=c.c_id
left join teacher t on c.t_id=t.t_id
where t.t_name='张旭';
#方法2
select s.s_id,s.degree from score s
join (teacher t,course c) on (s.c_id=c.c_id and c.t_id=t.t_id)
where t.t_name='张旭';
24、查询选修某课程的同学人数多于5人的教师姓名。
#方法1--通过子查询
select teacher.t_name from teacher where t_id in
(select t_id from course where c_id in
(select c_id from score group by c_id having count(s_id)>5));
#方法2--通过连接查询（推荐）
select t.t_name from teacher t join
(course c,score s) on (t.t_id=c.t_id and c.c_id=s.c_id)
group by s.c_id having count(s.s_id)>5;
25、查询95033班和95031班全体学生的记录。
select * from student where class in (95033,95031);
26、查询存在有85分以上成绩的课程c_id.
#方法1
select distinct c_id from score where degree>85;
#方法2
select c_id from score group by c_id having MAX(degree)>85;
27、查询出“计算机系“教师所教课程的成绩表。
select s.degree,t.depart from score s join
(course c,teacher t) on (s.c_id=c.c_id and c.t_id=t.t_id)
where t.depart='计算机系';
28、查询“计算机系”与“电子工程系“不同职称的教师的t_name和prof。
select t_name,prof from teacher
where depart='计算机系'
and
prof not in (select prof from teacher where depart='电子工程系');
29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的c_id、s_id和degree,并按degree从高到低次序排序。
select * from score
where c_id='3-105'
and
degree>any(select degree from score where c_id='3-245')
order by degree desc;
30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的c_id、s_id和degree.
select * from score
where c_id='3-105'
and
degree>all(select degree from score where c_id='3-245');
31、查询所有教师和同学的name、sex和birthday.
select s.s_name 名字,s.s_sex 性别,s.s_birthday 年龄 from student s
union
select t.t_name 名字,t.t_sex 性别,t.t_birthday 年龄 from teacher t;
32、查询所有“女”教师和“女”同学的name、sex和birthday.
select s.s_name 名字,s.s_sex 性别,s.s_birthday 年龄 from student s where s.s_sex='女'
union
select t.t_name 名字,t.t_sex 性别,t.t_birthday 年龄 from teacher t where t.t_sex='女';
33、查询成绩比该课程平均成绩低的同学的成绩表。
select * from score a
join (select c_id,AVG(degree) average from score group by c_id) b
on a.c_id=b.c_id
where a.degree<b.average;
34、查询所有任课教师的t_name和depart. (不是所有老师都教课)
select t.t_name,t.depart from teacher t join course c on t.t_id=c.t_id;
35、查询所有未讲课的教师的t_name和depart.
#方法1--子查询
select t_name,depart from teacher where t_id not in (select t_id from course);
#方法2--exists
select t_name,depart from teacher where not exists (select * from course where course.t_id=teacher.t_id);
36、查询至少有2名男生的班号。
select class from student where s_sex='男' group by class having count(s_sex)>1;
37、查询student表中不姓“王”的同学记录。
select * from student where s_name not like '王%';
38、查询student表中每个学生的姓名和年龄。
select s_name as 姓名,(YEAR(NOW())-YEAR(s_birthday)) as 年龄 from student;
39、查询student表中最大和最小的s_birthday日期值。
select DATE_FORMAT(MAX(s_birthday),'%Y-%d-%m') as 最大日期,DATE_FORMAT(MIN(s_birthday),'%Y-%d-%m') as 最小日期 from student;
40、以班号和年龄从大到小的顺序查询student表中的全部记录。
select * from student order by class desc,s_birthday desc;
41、查询“男”教师及其所上的课程。
select * from course c
join teacher t on c.t_id=t.t_id
where t.t_sex='男';
42、查询最高分同学的s_id、c_id和degree列。
select * from score order by degree desc limit 1;
43、查询和“李军”同性别的所有同学的s_name.
select s_name from student where s_sex=(select s_sex from student where s_name='李军');
44、查询和“李军”同性别并同班的同学s_name.
select s_name from student where (s_sex,class)=(select s_sex,class from student where s_name='李军');
45、查询所有选修“计算机导论”课程的“男”同学的成绩表。
select sc.* from score sc
join (student st,course c) on (sc.s_id=st.s_id and sc.c_id=c.c_id)
where st.s_sex='男' and c.c_name='计算机导论';
