create table score ( id  INT(10)  NOT NULL  UNIQUE  PRIMARY KEY  AUTO_INCREMENT , stu_id  INT(10)  NOT NULL , c_name  VARCHAR(20) , grade  INT(10) );select * from student;select id,name,sex,birth,department,address from student;select * from student limit 3 offset 1;select id,name,department from student;select * from student where "2008"-birth >= "12" AND "2008"-birth <= "22";select * from student where "2008"-birth BETWEEN 12 AND 22;select department,count(department) as "人数" from student group by department;select c_name,max(grade) from score group by c_name;select s.name,c.c_name,c.grade from score c INNER JOIN student s ON s.id = c.stu_id where s.name = "李四";select s.*,c* from score c INNER JOIN student s ON s.id = c.stu_id;select s.name,avg(c.grade) as "平均分" from score c INNER JOIN student s ON s.id = c.stu_id group by s.name;select s.name,c.* from score c INNER JOIN student s ON s.id = c.stu_id where c.c_name = '计算机' order by c.grade desc;select   *  from employee  where  name NOT IN ('张三','李四') ;systemctl set-default multi-user.targetcd ~/.ssh/ssh localhostcd ~/.ssh/ssh-keygen -t rsassh-copy-id 主机名select * from employee limit 2 offset 3;select * from employee where age <=30 AND age >=25;select d_id,SUM(salary) from employee group by d_id;select * from employee order by salary desc;select * from employee where address like "北京市%";select * from employee where name like "_ric";select * from employee where name like "L__y";https://www.budingcy.net/archives/34039https://zh.moegirl.org.cn/%E5%B0%9A%E6%9C%89%E4%BD%B3%E8%9C%9C%E4%BC%B4%E6%81%8B%E5%BF%83