管理和使用命令操作MySQL数据库（基本操作，SQL语言，DDL,DML,DQL,DCL）

一.常规操作命令

1.1 设置root 用户密码，及登录

[root@shanan mysql]# mysql -u root -p

Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.17 Source distribution

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>
[root@shanan ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.17 Source distribution

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rightsreserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

1.2查看数据库信息

mysql> show databases;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

mysql>
mysql> use mysql;       进入mysql 数据库
Database changed
mysql> show tables;      查看数据库中的表信息
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |

| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
31 rows in set (0.00 sec)

1.3 查看数据库中的表结构

ysql> mysql> describe user;   

+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field                  | Type                              | Null | Key | Default               | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host                   | char(60)                          | NO   | PRI |                       |       |
| User                   | char(32)                          | NO   | PRI |                       |       |
| Select_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Insert_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Update_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Delete_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Create_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Drop_priv              | enum('N','Y')                     | NO   |     | N                     |       |
| Reload_priv            | enum('N','Y')                     | NO   |     | N                     |       |
| Shutdown_priv          | enum('N','Y')                     | NO   |     | N                     |       |
| Process_priv           | enum('N','Y')                     | NO   |     | N                     |       |
| File_priv              | enum('N','Y')                     | NO   |     | N                     |       |

用此命令 效果一样

mysql> desc user;

+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field                  | Type                              | Null | Key | Default               | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host                   | char(60)                          | NO | PRI |                       |       |
| User                   | char(32)                          | NO | PRI |                       |       |
| Select_priv            | enum('N','Y')                     | NO |     | N                     |       |




mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |

| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
31 rows in set (0.00 sec)

1.4 SELECT查看用户信息表

DQL是数据查询语句，只有一条：SELECT
用于从数据表中查找符合条件的数据记录
不指定条件查询命令是
SELECT字段名1，字段名2…FROM表名

mysql> select * from user;

+-----------+-----------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+-----------------------+-------------------------------------------+------------------+-----------------------+-------------------+----------------+
| Host      | User      | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv| Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin                | authentication_string                | password_expired | password_last_changed | password_lifetime | account_locked |
+-----------+-----------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+-----------------------+-------------------------------------------+------------------+-----------------------+-------------------+----------------+
| localhost | root      | Y           | Y           | Y           | Y           | Y           | Y         | Y           | Y  | Y            | Y         | Y          | Y               | Y      | Y          | Y            | Y          | Y    | Y                | Y            | Y               | Y        | Y                | Y              | Y                   | Y                  | Y                | Y          | Y| Y                      |          |            |             |           |             0 |           0 |               0 |             0 | mysql_native_password | *204C8A3B79DC1533866049F6819865291C5E6AD5 | N                | 2020-08-15 10:05:06   |       NULL | N              |
| localhost | mysql.sys | N           | N           | N           | N           | N           | N         | N           | N  | N            | N         | N          | N               | N      | N          | N            | N          | N    | N                | N            | N               | N        | N                | N              | N                   | N                  | N                | N          | N| N                      |          |            |             |           |             0 |           0 |               0 |             0 | mysql_native_password | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | N                | 2020-08-15 10:00:43   |       NULL | Y              |
+-----------+-----------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+-----------------------+-------------------------------------------+------------------+-----------------------+-------------------+----------------+
2 rows in set (0.00 sec)

1.4.1 查看几个用户

mysql> select user from user;    

+-----------+
| user      |
+-----------+
| mysql.sys |
| root      |
+-----------+
2 rows in set (0.00 sec)

mysql>

1.5 创建数据库 school

mysql> create database school;

查看数据库列表

mysql> show databases;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| school             |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> use school;

Database changed
mysql>  show tables;
Empty set (0.00 sec)

1.5.1定义表字段

**mysql> create table info (id int(3) not null primary key auto_increment,name varchar(10) not null,score decimal(5,2),address varchar(50) default'未知');**
Query OK, 0 rows affected (0.01 sec)

mysql>

1.5.2 显示表内容

mysql> describe info;

---------+--------------+------+-----+---------+----------------+
| Field   | Type         | Null | Key | Default | Extra          |
+---------+--------------+------+-----+---------+----------------+
| id      | int(3)       | NO   | PRI | NULL    | auto_increment |
| name    | varchar(10)  | NO   |     | NULL    |                |
| score   | decimal(5,2) | YES  |     | NULL    |                |
| address | varchar(50)  | YES  |     | 未知    |                |
+---------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

给root提权

mysql> grant all privileges on *.* to 'root'@'%' identified by 'asd123';

Query OK, 0 rows affected, 1 warning (0.00 sec)

1.5.3 在表中写入数据

写入数据（字符串要用 单 引号 ‘’ 引起来, 一一对应，数量相同，顺序一致 ）

mysql> insert into info (id,name,score,address) values (1,'zhasan',88.50,'nanjing');

Query OK, 1 row affected (0.01 sec)

1.5.4 查看数据内容

mysql> select * from info;

±—±---------±------±--------+
| id | name | score | address |
±—±---------±------±--------+
| 1 | zhangsan | 88.50 | nanjing |
±—±---------±------±--------+
1 row in set (0.00 sec)

1.5.5 继续添加内容的几种方式

（不跟字段名，默认所有字段，但是需要将数值写全）
mysql> insert into info values (2,‘lisi’,77,‘shanghai’);
Query OK, 1 row affected (0.01 sec)

查看数据

mysql> select * from info;
+----+----------+-------+----------+
| id | name     | score | address  |
+----+----------+-------+----------+
|  1 | zhangsan | 88.50 | nanjing  |
|  2 | lisi     | 77.00 | shanghai |
+----+----------+-------+----------+
2 rows in set (0.00 sec)

继续添加内容
mysql> insert into info (name,score,address) values (‘wangwu’,99,‘suzhou’),(‘zhaoliu’,68,default);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0

mysql> select* from info ;
+----+----------+-------+----------+
| id | name     | score | address  |
+----+----------+-------+----------+
|  1 | zhangsan | 88.50 | nanjing  |
|  2 | lisi     | 77.00 | shanghai |
|  3 | wangwu   | 99.00 | suzhou   |
|  4 | zhaoliu  | 68.00 | 未知     |
+----+----------+-------+----------+
4 rows in set (0.00 sec)

1.6 筛选出分数大于80 的人

mysql> select * from info where score > 80;

+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.50 | nanjing |
|  3 | wangwu   | 99.00 | suzhou  |
+----+----------+-------+---------+
2 rows in set (0.00 sec)

1.6.1 将分数大于80 的 数据内容导出到新表 sha

mysql> create table sha as select * from info where score >80;
Query OK, 2 rows affected (0.02 sec)
Records: 2 Duplicates: 0 Warnings: 0

mysql> show tables;
+------------------+
| Tables_in_school |
+------------------+
| info             |
| sha              |
+------------------+
2 rows in set (0.00 sec)

mysql> select * from sha;
+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.50 | nanjing |
|  3 | wangwu   | 99.00 | suzhou  |
+----+----------+-------+---------+
2 rows in set (0.00 sec)

mysql>

1.7 修改，更新数据表中的数据记录的命令

update 表名 set 字段名 1=值1[，字段名2=值2] where条件表达式

设置zhangsan的成绩
mysql> update info set score=55 where name=‘zhangsan’;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0

显示表内容
mysql> select * from sha;

+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.50 | nanjing |
|  3 | wangwu   | 99.00 | suzhou  |
+----+----------+-------+---------+
2 rows in set (0.00 sec)

mysql> select * from info;
+----+----------+-------+----------+
| id | name     | score | address  |
+----+----------+-------+----------+
|  1 | zhangsan | 55.00 | nanjing  |
|  2 | lisi     | 77.00 | shanghai |
|  3 | wangwu   | 99.00 | suzhou   |
|  4 | zhaoliu  | 68.00 | 未知     |
+----+----------+-------+----------+
4 rows in set (0.00 sec)

二 .SQL语言概述及管理

SQL语言

是Structured Query Language的缩写，及结构化查询语言
是关系型数据库的标准语言
用于维护管理数据库，如数据查询，数据更新，访问控制，对象管理等功能
SQL分类

DDL：数据定义语言

DML：数据操纵语言

DQL：数据查询语言

DCL：数据控制语言

SQL操作管理命令
DDL操作命令：
DDL语句是什么作用？
DDL语句用于创建数据库对象，如库，表，索引等
DDL语句创建库，表的命令
创建数据库：create database 数据库名

创建数据表：create table 表名（字段定义…）
. Mysql 用户密码的修改

2.1 创建用户Tom

mysql> GRANT all ON localhost. TO ‘Tom’@’%’ IDENTIFIED BY ‘asd123’;*
Query OK, 0 rows affected, 1 warning (0.00 sec)

2.2 设置跳过密码检查，直接登录进去

[root@shanan ~]# vim /etc/my.cnf

2.3 重启服务，测试无密码登录

[root@shanan ~]# systemctl restart mysqld
[root@shanan ~]# mysql -u root -p

Enter password:   //  不用密码 ，回车即可登录
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.17 Source distribution

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/orits
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the currentinput statement.

mysql>
mysql> show databases;
+--------------------+
|
| school             |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
。。。。。。。。。
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
31 rows in set (0.00 sec)

mysql> select * from user;

2.4 重新设置Tom 的密码

mysql> update mysql.user set authentication_string=password(‘sha1234567’) where user=‘tom’;
Query OK, 0 rows affected, 1 warning (0.00 sec)
Rows matched: 0 Changed: 0 Warnings: 1
mysql> update mysql.user set authentication_string=password(‘sha1234567’) where user=‘Tom’;

2.4.1 刷新数据库

flush privileges;

三. 删除

DDL语句删除库，表的命令
删除指定的数据表：drop table [数据库名.]表名

删除指定的数据库：drop database 数据库名

3.1 在数据表中删除指定的数据记录命令

delete from 表名 where条件表达式
删除成绩大于90 分的

mysql> delete from sha where score >= 90;
Query OK, 1 row affected (0.01 sec)

mysql> select * from sha;
+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.50 | nanjing |
+----+----------+-------+---------+
1 row in set (0.00 sec)

3.2 删除表 sha 所有数据

不带where条件的语句表示删除表中所有记录（谨慎操作）
mysql> select * from sha;

+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.50 | nanjing |
+----+----------+-------+---------+
1 row in set (0.00 sec)

3.2.1 删除表数据，添加表数据

DML操作命令
DML语句的作用
DML语句用于对表中的数据进行管理
包括以下操作
insert：插入新数据
update：更新原有数据
delete：删除不需要的数据
向数据表中插入新的数据记录命令是？
insert into 表名（字段1，字段2，…）values（字段1的值，字段2的值，…）

删除表数据

mysql> delete from sha;
Query OK, 1 row affected (0.00 sec)

mysql> select * from sha;
Empty set (0.00 sec)

delete 清空内容，表还在

mysql> truncate table info;
Query OK, 0 rows affected (0.01 sec)

mysql> select * from info;
Empty set (0.00 sec)

Drop 删除，连同表一块删除

mysql> drop table info;

Query OK, 0 rows affected (0.00 sec)

mysql> show tables;     // 发现表也没有了
+------------------+
| Tables_in_school |
+------------------+
| sha              |
+------------------+
1 row in set (0.00 sec)

mysql> drop tables sha;
Query OK, 0 rows affected (0.00 sec)

mysql> show tables;
Empty set (0.00 sec)

四. 创建临时表：

4.1 创建临时表

mysql> create temporary table temp_info (id int(4) not null auto_increment,name varchar(10) not null,hobby varchar(10) not null,primary key(id))engine=innodb default charset=utf8;
Query OK, 0 rows affected (0.00 sec)

4.2 查看临时表

mysql> desc temp_info;

+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra|
+-------+-------------+------+-----+---------+----------------+
| id    | int(4)      | NO   | PRI | NULL    | auto_increment|
| name  | varchar(10) | NO   |     | NULL    ||
| hobby | varchar(10) | NO   |     | NULL    ||
+-------+-------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

4.3 在 表中写入内容

mysql> insert into temp_info (name,hobby) values(‘tom’,‘cat’);
Query OK, 1 row affected (0.01 sec)

查看内容
mysql> select * from temp_info;

+----+------+-------+
| id | name | hobby |
+----+------+-------+
|  1 | tom  | cat   |
+----+------+-------+
1 row in set (0.00 sec)

4.4 **查看表

发现查不到创建的临时表，因为表存在内存中，退出就会自动清除
mysql> show tables;**

+------------------+
| Tables_in_school |
+------------------+
| sha              |
+------------------+
1 row in set (0.00 sec)

mysql>

退出之后查看，发现临时表果然消失了

Database changed
mysql> show tables;
+------------------+
| Tables_in_school |
+------------------+
| sha              |
+------------------+
1 row in set (0.00 sec)

mysql> select * from temp_info;
ERROR 1146 (42S02): Table 'school.temp_info' doesn't exist

创建表 shanan

create table shanan (id int(3) not null primary key auto_increment,name varchar(10) not null,score decimal(5,2),address varchar(50) default'未知');

五. 克隆表

5.1 显示表结构

mysql> desc shanan;

+---------+--------------+------+-----+---------+----------------+
| Field   | Type         | Null | Key | Default | Extra   |
+---------+--------------+------+-----+---------+----------------+
| id      | int(3)       | NO   | PRI | NULL    | auto_increment |
| name    | varchar(10)  | NO   |     | NULL    |   |
| score   | decimal(5,2) | YES  |     | NULL    |   |
| address | varchar(50)  | YES  |     | 未知    |   |
+---------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

5.2 克隆表结构shanan

mysql> create table test like shanan;
Query OK, 0 rows affected (0.01 sec)

5.3 查看表列表，发现已生成克隆的 test

mysql> show tables;

+------------------+
| Tables_in_school |
+------------------+
| sha              |
| shanan           |
| test             |
+------------------+
3 rows in set (0.00 sec)

5.4 查看表结构，和克隆的对象完全一致

mysql> desc test;

+---------+--------------+------+-----+---------+----------------+
| Field   | Type         | Null | Key | Default | Extra   |
+---------+--------------+------+-----+---------+----------------+
| id      | int(3)       | NO   | PRI | NULL    | auto_increment |
| name    | varchar(10)  | NO   |     | NULL    |   |
| score   | decimal(5,2) | YES  |     | NULL    |   |
| address | varchar(50)  | YES  |     | 未知    |   |
+---------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

5.5 在表中写入内容将表内容克隆到新表

mysql> select * from test;

+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.00 | nanjing |
+----+----------+-------+---------+
1 row in set (0.00 sec)

将内容克隆到表 由 test 克隆到 shanan
mysql> insert into shanan select * from test;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0

mysql> select * from shanan;
+----+----------+-------+---------+
| id | name     | score | address |
+----+----------+-------+---------+
|  1 | zhangsan | 88.00 | nanjing |
+----+----------+-------+---------+
1 row in set (0.00 sec)

六. 用权限的增加与撤销

DCL语句的作用是
设置或查看用户的权限，或者创建用户
设置用户权限的命令是
若用户已存在，则更改用户密码

若用户不存在，则新建用户

GRANT 权限列表 ON 数据库名.表名 TO 用户名@来源地址 [IDENTIFIED BY ‘密码′ ]

6.1 查看mysql用户

mysql> select user from mysql.user;

+-----------+
| user      |
+-----------+
| Tom       |
| root      |
| mysql.sys |
| root      |
+-----------+
4 rows in set (0.01 sec)

6.2 创建用户jerrry ，并提权

mysql> grant all on . to ‘jerry’@‘localhost’ identified by ‘abc123’ ;
Query OK, 0 rows affected, 1 warning (0.00 sec)
刷新
mysql> flush privileges;

6.3查看查看用户权限的命令是？

SHOW GRANTS FOR 用户名@来源地址
当前的grants

mysql> show grants;

+---------------------------------------------------------------------+
| Grants for root@localhost        |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION        |
+---------------------------------------------------------------------+
2 rows in set (0.00 sec)

6.4 查看jerry 的权限

mysql> show grants for ‘jerry’@‘localhost’;

+----------------------------------------------------+
| Grants for jerry@localhost                         |
+----------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'jerry'@'localhost' |
+----------------------------------------------------+
1 row in set (0.00 sec)

6.5 撤销用户权限的命令

REVOKE 权限列表 ON 数据库名.表名 FROM 用户名@来源地址

撤销JERRY用户的权限

mysql> revoke all on . from ‘jerry’@‘localhost’;
Query OK, 0 rows affected (0.00 sec)

6.6 查看权限已被撤销

mysql> show grants for ‘jerry’@‘localhost’;

+-------------------------------------------+
| Grants for jerry@localhost                |
+-------------------------------------------+
| GRANT USAGE ON *.* TO 'jerry'@'localhost' |
+-------------------------------------------+
1 row in set (0.00 sec)

6.7 权限操作命令总结

Grand :当用户已存在时，直接提权，当用户不存在时，先创建用户再提权
Revoke : 只撤销权限，不会删除用户