---------------------创建数据库----------
 CREATE DATABASE IF NOT EXISTS `mm` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ;
 ------------------建表--------------------
 CREATE TABLE biao (
    id INT PRIMARY KEY,
    id_name VARCHAR(50),
    age INT
);
----------------新增数据-----------------------
insert into biao (id,id_name,age) VALUES (1,'张三',15);
insert into biao (id,id_name,age) VALUES (2,'李四',16);
insert into biao (id,id_name,age) VALUES (3,'王五',17);
insert into biao (id,id_name,age) VALUES (4,'赵六',18);
insert into biao (id,id_name,age) VALUES (6,'小刘',19);
select * from biao;
----------------编辑数据（update）--------------------
UPDATE biao set age =20 where id=5;
-----------------删除数据（delete）-------------------
DELETE FROM biao WHERE id=2;
-----------------删除表------------------------------
drop TABLE biao;
-----------------截断表------------------------------
truncate table biao;
-----------------创建视图----------------------------
DROP VIEW IF EXISTS myname_view;
CREATE VIEW myname_view AS SELECT * FROM biao;
-----------------查询视图----------------------------
SELECT * from myname_view;
-----------------修改视图---------------
UPDATE myname_view SET id_name='小刘' WHERE id=1;-----------不可用----对基本表进行修改操作，视图（虚拟表）也会随着修改
-----------------删除视图----------------------------
drop VIEW myname_view;
------------------视图新增数据--------------
insert into myname_view (id,id_name,age) VALUES (6,'钱九',26); ---------不支持----对基本表进行新增操作，视图（虚拟表）也会随着新增
-------------------视图删除数据
delete from  myname_view where id=5;----------------------不支持----对基本表进行删除操作，视图（虚拟表）也会随着删除
-------------------创建索引---------------------------
create index biao_id ON biao(id);
-------------------使用alter创建索引---------------------------
ALTER TABLE biao ADD INDEX biao_id1 (id);
-------------------对于值唯一的列创建唯一索引--------------------
CREATE UNIQUE INDEX biao_id_unique ON biao (id);
-------------------查询所有索引----------------------------
SHOW INDEX FROM biao;
-------------------删除索引(两种方式)------------------------------
DROP INDEX biao_id ON biao;
ALTER TABLE biao DROP INDEX biao_id1;
--------------------创建用户-------------------------
CREATE USER '用户名'@'访问地址' IDENTIFIED BY '123456';
--------------------授权对某个库内的查询权限-----------------
GRANT SELECT ON 库名.* TO '用户名'@'localhost';  ----localhost代表访问地址，可以自行修改到服务器
--------------------查询用户对某个服务连接所拥有的权限-------------------------
SHOW GRANTS for 用户名@访问地址;
--------------------删除用户--------------------
DROP USER '用户名'@'访问地址';