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MySQL用户管理、常用SQL语句、MySQL数据库备份恢复

MySQL用户管理

1.创建一个普通用户并授权
[root@gary-tao ~]# mysql -uroot -p'szyino-123'
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 24
Server version: 5.6.35 MySQL Community Server (GPL)

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> grant all on *.* to 'user1'@'127.0.0.1' identified by 'szyino-123';  //创建一个普通用户并授权
Query OK, 0 rows affected (0.00 sec)
用法解释说明：
  • grant：授权；
  • all:表示所有的权限（如读、写、查询、删除等操作）；
  • .：前者表示所有的数据库,后者表示所有的表；
  • identified by：后面跟密码，用单引号括起来；
  • 'user1'@'127.0.0.1':指定IP才允许这个用户登录，这个IP可以使用%代替，表示允许所有主机使用这个用户登录;
2.测试登录
[root@gary-tao ~]# mysql -uuser1 -pszyino-123 //由于指定IP，报错不能登录
Warning: Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'user1'@'localhost' (using password: YES)
[root@gary-tao ~]# mysql -uuser1 -pszyino-123 -h227.0.0.1 //加-h指定IP登录，正常
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 26
Server version: 5.6.35 MySQL Community Server (GPL)

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> 

mysql> grant all on *.* to 'user1'@'localhost' identified by 'szyino-123';  //授权localhost，所以该用户默认使用（监听）本地mysql.socket文件，不需要指定IP即可登录
Query OK, 0 rows affected (0.00 sec)

mysql> ^DBye
[root@gary-tao ~]# mysql -uuser1 -pszyino-123  //正常登录
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 28
Server version: 5.6.35 MySQL Community Server (GPL)

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>
3.查看所有授权
mysql> show grants;
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost                                                                                                              |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*B1E761CAD4A61F6FD6B02848B5973BC05DE1C315' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                                           |
+----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
4.指定用户查看授权
mysql> show grants for user1@'127.0.0.1';
+-----------------------------------------------------------------------------------------------------------------------+
| Grants for user1@127.0.0.1                                                                                            |
+-----------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'user1'@'127.0.0.1' IDENTIFIED BY PASSWORD '*B1E761CAD4A61F6FD6B02848B5973BC05DE1C315' |
+-----------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
注意：假设你想给同个用户授权增加一台电脑IP授权访问，你就可以直接拷贝查询用户授权文件，复制先执行一条命令再执行第二条，执行的时候把IP更改掉,这样就可以使用同个用户密码在另外一台电脑上登录。

常用sql语句

1.最常见的查询语句

第一种形式:

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mysql> use db1;
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> select count(*) from mysql.user; 
+----------+
| count(*) |
+----------+
|        8 |
+----------+
1 row in set (0.00 sec)

//注释：mysql.user表示mysql的user表，count(*)表示表中共有多少行。

第二种形式:

mysql> select * from mysql.db;

//它表示查询mysql库的db表中的所有数据

mysql> select db from mysql.db;
+---------+
| db      |
+---------+
| test    |
| test\_% |
+---------+
2 rows in set (0.00 sec)

//查询db表里的db单个字段

mysql> select db,user from mysql.db;
+---------+------+
| db      | user |
+---------+------+
| test    |      |
| test\_% |      |
+---------+------+
2 rows in set (0.00 sec)

//查看db表里的db，user多个字段

mysql> select * from mysql.db where host like '192.168.%'\G;

//查询db表里关于192.168.段的ip信息
2.插入一行
mysql> desc db1.t1;
+-------+----------+------+-----+---------+-------+
| Field | Type     | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| id    | int(4)   | YES  |     | NULL    |       |
| name  | char(40) | YES  |     | NULL    |       |
+-------+----------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> select * from db1.t1;  
Empty set (0.00 sec)

mysql> insert into db1.t1 values (1, 'abc');  //插入一行数据
Query OK, 1 row affected (0.01 sec)

mysql> select * from db1.t1;
+------+------+
| id   | name |
+------+------+
|    1 | abc  |
+------+------+
1 row in set (0.00 sec)
mysql> insert into db1.t1 values (1, '234');
Query OK, 1 row affected (0.00 sec)

mysql> select * from db1.t1;
+------+------+
| id   | name |
+------+------+
|    1 | abc  |
|    1 | 234  |
+------+------+
2 rows in set (0.00 sec)
3.更改表的一行。
mysql> update db1.t1 set name='aaa' where id=1;
Query OK, 2 rows affected (0.01 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> select * from db1.t1;
+------+------+
| id   | name |
+------+------+
|    1 | aaa  |
|    1 | aaa  |
+------+------+
2 rows in set (0.00 sec)
4.清空某个表的数据
mysql> truncate table db1.t1;  //清空表
Query OK, 0 rows affected (0.03 sec)

mysql> select * from db1.t1;
Empty set (0.00 sec)
mysql> desc db1.t1;
+-------+----------+------+-----+---------+-------+
| Field | Type     | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| id    | int(4)   | YES  |     | NULL    |       |
| name  | char(40) | YES  |     | NULL    |       |
+-------+----------+------+-----+---------+-------+
2 rows in set (0.00 sec)
5.删除表
mysql> drop table db1.t1;
Query OK, 0 rows affected (0.01 sec)

mysql> select * from db1.t1;
ERROR 1146 (42S02): Table 'db1.t1' doesn't exist
6.删除数据库
mysql> drop database db1;
Query OK, 0 rows affected (0.00 sec)

mysql数据库备份恢复

1.备份恢复库
[root@gary-tao ~]# mysqldump -uroot -pszyino-123 mysql > /tmp/mysql.sql  //备份库
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# mysql -uroot -pszyino-123 -e "create database mysql2"  //创建一个新的库
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# mysql -uroot -pszyino-123 mysql2 < /tmp/mysql.sql  //恢复一个库
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# mysql -uroot -pszyino-123 mysql2
Warning: Using a password on the command line interface can be insecure.
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 38
Server version: 5.6.35 MySQL Community Server (GPL)

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> select database();
+------------+
| database() |
+------------+
| mysql2     |
+------------+
1 row in set (0.00 sec)
2.备份恢复表
[root@gary-tao ~]# mysqldump -uroot -pszyino-123 mysql user > /tmp/user.sql  //备份表
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# mysql -uroot -pszyino-123 mysql2 < /tmp/user.sql  //恢复表
Warning: Using a password on the command line interface can be insecure.
3.备份所有库
[root@gary-tao ~]# mysqldump -uroot -pszyino-123 -A > /tmp/mysql_all.sql
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# less /tmp/mysql_all.sql
4.只备份表结构
[root@gary-tao ~]# mysqldump -uroot -pszyino-123 -d mysql > /tmp/mysql.sql
Warning: Using a password on the command line interface can be insecure.

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