mysql用户修改登录密码及开启远程登录

一、修改用户登录密码：

mysql> show databases;
ERROR 1820 (HY000): You must SET PASSWORD before executing this statement
mysql> quit
Bye
[root@rhel204 ~]# mysqladmin -uroot -p password --修改用户密码
Enter password:
New password:
Confirm new password:

[root@rhel204 ~]# mysql -uroot -p --以新密码登录
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
……
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.10 sec)

二、开启用户远程登录权限
--加-h参数远程登录mysql数据库提示如下错误
C:\Users\Administrator>mysql -uroot -p -h192.168.1.204
Enter password: *****
ERROR 1130 (HY000): Host '192.168.1.123' is not allowed to connect to this MySQL server
错误分析：主机'192.168.1.123'不允许连接到mysql数据库（没权限）。

[root@rhel204 ~]# myslq -uroot -p --本地登录
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> select user,password,host from user; --查看用户信息，的确root账号只允许本地登录。
+------+-------------------------------------------+-------------+
| user | password | host |
+------+-------------------------------------------+-------------+
| root | *76C1B58DE0F08B3169E76CEDD6DD814B32A36F78 | localhost |
| root | *76C1B58DE0F08B3169E76CEDD6DD814B32A36F78 | rhel204.com |
| root | *76C1B58DE0F08B3169E76CEDD6DD814B32A36F78 | 127.0.0.1 |
| root | *76C1B58DE0F08B3169E76CEDD6DD814B32A36F78 | ::1 |
+------+-------------------------------------------+-------------+
4 rows in set (0.00 sec)

mysql> grant all privileges on *.* to root@'%' identified by 'rusky'; --授权
Query OK, 0 rows affected (0.03 sec)
或：grant all on db1.* to username1@'%'; --授权用户username1从任一客户端远程登录数据库db1，并允许对库db1做所有操作。
"%"表示任何主机都可以远程登录到该服务器*问。
*.*表示所有库的所有对象。
如果要限制只有某台机器可以访问，将%换成相应的IP即可，如：
GRANT ALL PRIVILEGES ON *.* TO username2@‘192.168.1.123’; --可省略IDENTIFIED BY '密码';或with grant option;

mysql> flush privileges; --刷新权限
Query OK, 0 rows affected (0.04 sec)

C:\Users\Administrator>mysql -uroot -p -h192.168.1.204 --root账号远程登录
Enter password: *****
Welcome to the MySQL monitor. Commands end with ; or \g.
……
mysql>

三、创建用户时就限制用户的权限：

create user   'lxj'@'%'    identified  by '123123';

@后面参数指定该用户在哪个主机上可以登陆,如果是本地用户可用localhost, 如果想让该用户可以从任意远程主机登陆,可以使用通配符%.