1 show databases; 2 create database first; 3 drop database first; 4 use example; 5 create table example0( 6  id int primary key auto_increment, 7  name varchar(20) 8  ); 9 show tables;10 describe example0;11 show create table example1 \G12 primary key,13 14 constraint c_fk foreign key(stu_id,course_id) references exma2(stu_id,course_id)15 16 unique17 math float default 018 19 alter table ex0 rename ex1;20 alter table ex0 modify sex int(4);21 alter table ex0 change id stu_id int;22 alter table ex0 add age int not null;23 alter table ex0 add id int primary key first;24 alter table ex0 add address varchar(30) not null after name;25 alter table ex0 drop sex;26 alter table ex0 modify address varchar(30) after name;27 alter table ex0 modify address varchar(30) first;28 alter table ex0 drop foreign key c_fk;29 drop table ex0;30 31 insert into 表名 values(, , , );32 33 select * from 表名；34 select * from 表名 where id in(1000,1001);35 select * from 表名 where age between 18 and 20;36 select * from biao where name like "李明";37 select * from biao where name like "李%";38 select * from biao where name like "%李%";39 select * from b where name like "李_";40 select * from b where name not like "李%";41 select * from ex0 order by id asc;42 select * from ex0 order by age desc;43 select avg(math),avg(English),avg(sum) from a1;44 select id,name,max(sum) from a1;45 select id,name,sex,max(sum) from a1 group by sex;46 47 update tab_name set col_name1="",col_name2=" " where name="" order by 48 update tab_name set sum=math+English;49 50 delete tab_name from tab_name where id=1005;