50道经典SQL练习题 MYSQL8.0实现

使用MYSQL8.0完成了“50道经典SQL练习题”，答案可能有误，欢迎指正。
参考了多位网友的答案
超经典SQL练习题，做完这些你的ＳＱＬ就过关了
50道SQL练习题
50道SQL练习题及答案与详细分析

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准备数据

CREATE TABLE student(
  id VARCHAR(10),
  name VARCHAR(10),
  age DATETIME,
  sex VARCHAR(10)
);

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('09' , '张三' , '2017-12-20' , '女');
insert into student values('10' , '李四' , '2017-12-25' , '女');
insert into student values('11' , '李四' , '2017-12-30' , '女');
insert into student values('12' , '赵六' , '2017-01-01' , '女');
insert into student values('13' , '孙七' , '2018-01-01' , '女');

create table course(
  id varchar(10),
  name varchar(10),
  teacher_id varchar(10)
);

insert into course values('01' , '语文' , '02');
insert into course values('02' , '数学' , '01');
insert into course values('03' , '英语' , '03');

create table teacher(
  id varchar(10),
  name varchar(10)
);

insert into teacher values('01' , '张三');
insert into teacher values('02' , '李四');
insert into teacher values('03' , '王五');

create table score(
  student_id varchar(10),
  cource_id varchar(10),
  score decimal(18,1)
);

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);

题解

1. 查询" 01 “课程比” 02 "课程成绩高的学生的信息及课程分数

SELECT * FROM (SELECT student_id, score FROM score WHERE cource_id = '01') sc1,
 (SELECT student_id, score FROM score WHERE cource_id = '02') sc2 WHERE
 sc1.score > sc2.score AND sc1.student_id = sc2.student_id;

SELECT * FROM (SELECT student_id, score FROM score WHERE cource_id