sql练习

--建表
--学生表
CREATE TABLE `Student`(
    `s_id` VARCHAR(20),
    `s_name` VARCHAR(20) NOT NULL DEFAULT ‘‘,
    `s_birth` VARCHAR(20) NOT NULL DEFAULT ‘‘,
    `s_sex` VARCHAR(10) NOT NULL DEFAULT ‘‘,
    PRIMARY KEY(`s_id`)
);
--课程表
CREATE TABLE `Course`(
    `c_id`  VARCHAR(20),
    `c_name` VARCHAR(20) NOT NULL DEFAULT ‘‘,
    `t_id` VARCHAR(20) NOT NULL,
    PRIMARY KEY(`c_id`)
);
--教师表
CREATE TABLE `Teacher`(
    `t_id` VARCHAR(20),
    `t_name` VARCHAR(20) NOT NULL DEFAULT ‘‘,
    PRIMARY KEY(`t_id`)
);
--成绩表
CREATE TABLE `Score`(
    `s_id` VARCHAR(20),
    `c_id`  VARCHAR(20),
    `s_score` INT(3),
    PRIMARY KEY(`s_id`,`c_id`)
);
--插入学生表测试数据
insert into Student values(‘01‘ , ‘赵雷‘ , ‘1990-01-01‘ , ‘男‘);
insert into Student values(‘02‘ , ‘钱电‘ , ‘1990-12-21‘ , ‘男‘);
insert into Student values(‘03‘ , ‘孙风‘ , ‘1990-05-20‘ , ‘男‘);
insert into Student values(‘04‘ , ‘李云‘ , ‘1990-08-06‘ , ‘男‘);
insert into Student values(‘05‘ , ‘周梅‘ , ‘1991-12-01‘ , ‘女‘);
insert into Student values(‘06‘ , ‘吴兰‘ , ‘1992-03-01‘ , ‘女‘);
insert into Student values(‘07‘ , ‘郑竹‘ , ‘1989-07-01‘ , ‘女‘);
insert into Student values(‘08‘ , ‘王菊‘ , ‘1990-01-20‘ , ‘女‘);
--课程表测试数据
insert into Course values(‘01‘ , ‘语文‘ , ‘02‘);
insert into Course values(‘02‘ , ‘数学‘ , ‘01‘);
insert into Course values(‘03‘ , ‘英语‘ , ‘03‘);

--教师表测试数据
insert into Teacher values(‘01‘ , ‘张三‘);
insert into Teacher values(‘02‘ , ‘李四‘);
insert into Teacher values(‘03‘ , ‘王五‘);

--成绩表测试数据
insert into Score values(‘01‘ , ‘01‘ , 80);
insert into Score values(‘01‘ , ‘02‘ , 90);
insert into Score values(‘01‘ , ‘03‘ , 99);
insert into Score values(‘02‘ , ‘01‘ , 70);
insert into Score values(‘02‘ , ‘02‘ , 60);
insert into Score values(‘02‘ , ‘03‘ , 80);
insert into Score values(‘03‘ , ‘01‘ , 80);
insert into Score values(‘03‘ , ‘02‘ , 80);
insert into Score values(‘03‘ , ‘03‘ , 80);
insert into Score values(‘04‘ , ‘01‘ , 50);
insert into Score values(‘04‘ , ‘02‘ , 30);
insert into Score values(‘04‘ , ‘03‘ , 20);
insert into Score values(‘05‘ , ‘01‘ , 76);
insert into Score values(‘05‘ , ‘02‘ , 87);
insert into Score values(‘06‘ , ‘01‘ , 31);
insert into Score values(‘06‘ , ‘03‘ , 34);
insert into Score values(‘07‘ , ‘02‘ , 89);
insert into Score values(‘07‘ , ‘03‘ , 98);

select a.* ,b.s_score as 01_score,c.s_score as 02_score 
from student a 
join score b on a.s_id=b.s_id and b.c_id=‘01‘ 
left join score c on a.s_id = c.s_id and c.c_id = ‘02‘
where b.s_score > c.s_score;

select a.*,b.s_score as 01_score,c.s_score as 02_score 
from student a,score b,score c 
where a.s_id=b.s_id 
and a.s_id=c.s_id 
and b.c_id=‘01‘ 
and c.c_id=‘02‘ 
and b.s_score>c.s_score

select a.s_id,a.s_name,round(avg(b.s_score),2) as avg_score 
from student a
left join score b on a.s_id = b.s_id
group by a.s_id,a.s_name
having avg_score < 60 or avg_score is null

select a.s_id,a.s_name,round(avg(b.s_score),2) as avg_score 
from student a
left join score b on a.s_id = b.s_id
group by a.s_id,a.s_name
having avg_score >=60

select a.s_id,a.s_name,count(b.c_id) as total_course,sum(b.s_score) as total_score
from student a
left join score b on a.s_id = b.s_id
group by a.s_id,a.s_name

select count(t.t_id) from teacher t
where t.t_name like ‘李%‘

select a.*
from student a
inner join score b on a.s_id = b.s_id
where b.c_id in(
    select c_id from course where t_id = (
        select t_id from teacher where t_name = ‘张三‘
    )
)

select * from student c 
where c.s_id not in( 
    select a.s_id from student a 
    join score b on a.s_id=b.s_id 
    where b.c_id in( 
        select a.c_id from course a 
        join teacher b on a.t_id = b.t_id 
        where t_name =‘张三‘
    )
);

select a.* from student a
inner join score b on a.s_id = b.s_id
inner join score c on a.s_id = c.s_id
where b.c_id = ‘01‘
and c.c_id = ‘02‘;

select a.* from 
student a,score b,score c 
where a.s_id = b.s_id  
and a.s_id = c.s_id 
and b.c_id=‘01‘ 
and c.c_id=‘02‘;

select * from student 
where s_id in (select s_id from score where c_id=‘01‘)
and s_id not in (select s_id from score where c_id=‘02‘)

select a.* from student a
left join score b on a.s_id = b.s_id
group by a.s_id
having count(b.s_id) < (select count(c_id) from course);

select a.* from student a
inner join score b on a.s_id = b.s_id
where b.c_id in (
    select c_id from score where s_id =‘01‘
)
group by a.s_id;

select a.* from student a
inner join score b on a.s_id = b.s_id
where a.s_id <> ‘01‘
group by b.s_id
having group_concat(b.c_id ORDER BY c_id) = 
    (
        select group_concat(c_id ORDER BY c_id) 
        from score where s_id = ‘01‘
    );