mysql 5.7 设置root密码方法

[root@localhost ~]#  cat /etc/redhat-release
CentOS Linux release 7.1.1503

mysql> select version()
-> ;
+-----------+
| version() |
+-----------+
| 5.7.9     |
+-----------+
1 row in set (0.00 sec)

rpm -ivh http://repo.mysql.com//mysql57-community-release-el7-7.noarch.rpm[/code] 
安装mysql
yum install mysql-community-server
yum install mysql-community-client


修改mysql 配置文件跳过密码验证
[mysqld]
skip-grant-tables
skip-networking


启动mysql：
systemctl start mysqld


匿名登录mysql 设置root密码：
[root@localhost ~]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.9 MySQL Community Server (GPL)

Copyright (c) 2000, 2015, 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> update mysql.user set PASSWORD=PASSWORD('test') where user='root' and host='localhost';
ERROR 1054 (42S22): Unknown column 'PASSWORD' in 'field list'
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'test' ;
ERROR 1131 (42000): You are using MySQL as an anonymous user and anonymous users are not allowed to change passwords
mysql> update mysql.user set authentication_string=PASSWORD('test') where user='root' and host='localhost';
Query OK, 1 row affected, 1 warning (0.07 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> flush privileges;
Query OK, 0 rows affected (0.06 sec)

mysql> exit;
Bye


取消跳过密码认证：
[mysqld]
#skip-grant-tables
#skip-networking


重启mysql：
systemctl restart mysqld


必须使用alter user 重置密码：
mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.


重新设置密码：
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY '********'


密码需要复杂度要求：
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_dictionary_file    |        |
| validate_password_length             | 8      |
| validate_password_mixed_case_count   | 1      |
| validate_password_number_count       | 1      |
| validate_password_policy             | MEDIUM |
| validate_password_special_char_count | 1      |
+--------------------------------------+--------+
6 rows in set (0.00 sec)


ERROR 1820 (HY000): You must SET PASSWORD before executing this statement
mysql> set password=password('xxxx');
Query OK, 0 rows affected (0.00 sec)