1 #创建表
 2 create table table_name(column name, column type)
 3
 4 #创建一张学生表
 5 create table students(
 6     'sid' INT AUTO_INCREMENT PRIMARY KEY,
 7     'name' VARCHAR(50) NOT NULL,
 8     'age' INT NOT NULL,
 9 )engine=InnorDB DEFAULT charset=utf8
10
11 #查看表信息
12 desc student;

 1 增 语法：
 2 INSERT INTO table_name ( field1, field2,...fieldN ) VALUES ( value1, value2,...valueN );
 3
 4 查 语法：
 5 SELECT column_name,column_name FROM table_name [WHERE Clause] [OFFSET M ][LIMIT N]
 6
 7 改 语法：
 8 UPDATE table_name SET field1=new-value1, field2=new-value2 [WHERE Clause]
 9
10 删 语法：
11 DELETE FROM table_name [WHERE Clause] #delete from student where stu_id=5;

alter table table_name drop column_name; #删除字段
alter table table_name add column_name type NOT NULL; #添加字段
alter table table_name change old_column_name new_column_name type;  #修改字段名和类型

alert table table_name add foreign key(column_name) references table_name(column_name);  #添加外键

alert table table_name add index column_name;  #添加索引 

alter table old_table_name rename to new_table_name; #修改表名

select * from student order by age;  #默认升序
select * from student order by age asc; #升序
select * from student order by age desc;  #降序

1 begin;  #开始一个事务
2 insert into students (name) values(1);
3 commit;  #如果没出错则commit提交
4 rollback;  #如果出错就回滚，这样相当于没有执行过命令

1 create table classroom(
2     'cid' INT AUTO_INCREMENT PRIMARY KEY
3 );
4
5 create table student(
6     'name' VARCHAR(24) NOT NULL,
7     'class_id' INT NOT NULL,
8     foreign key(class_id) references classroom(id)
9 );

1 alert table student add foreign key(class_id) references classroom(id);

1 alert table student drop foreign key class_id;

select * from student where name like '%abc';  #表示查询以abc结尾的数据
select * from student where name like '_abc_';  #表示查询中间有abc的数据