centos mysql5.7安装

1 wget http://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
2 rpm -ivh mysql57-community-release-el7-11.noarch.rpm3 
3 yum install -y mysql-community-server

1 mysqladmin --version

mysqladmin  Ver 8.42 Distrib 5.7.27, for Linux on x86_64

1 systemctl start mysqld
2 systemctl enable mysqld        #设为开机启动

1 systemctl status mysqld

1 grep "password" /var/log/mysqld.log 

2019-10-09T05:38:13.539819Z 1 [Note] A temporary password is generated for root@localhost: yUFwLSCMW5!q

1 mysql -uroot -p
Enter password: 　　　　#输入密码即可登陆

1 mysql> ALTER USER ‘root‘@‘localhost‘ IDENTIFIED BY ‘root123‘;　　　　#修改密码为"root123"

ERROR 1819 (HY000): Your password does not satisfy the current policy requirements　　　　
#密码不符合策略

1 mysql> SHOW VARIABLES LIKE ‘validate_password%‘;

ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.　　　　
#先改密码才行

1 mysql> ALTER USER ‘root‘@‘localhost‘ IDENTIFIED BY ‘Password_123‘;

Query OK, 0 rows affected (0.00 sec)

1 mysql>  SHOW VARIABLES LIKE ‘validate_password%‘;

+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_check_user_name    | OFF    |　　　　#OFF密码可以等于用户名，ON密码不能等于用户名
| validate_password_dictionary_file    |        |　　　　#密码策略文件（检查强度为STRONG时需要）
| validate_password_length             | 8      |　　　　#密码最小长度
| validate_password_mixed_case_count   | 1      |　　　　#至少包含大/小写字母的总个数；
| validate_password_number_count       | 1      |　　　　#至少包含数字个数
| validate_password_policy             | MEDIUM |　　　　#检查强度等级
| validate_password_special_char_count | 1      |　　　　#至少包含的特殊字符个数
+--------------------------------------+--------+
7 rows in set (0.01 sec)
注：
#密码最小长度为：validate_password_number_count + validate_password_special_char_count + (2 * validate_password_mixed_case_count)
#检查强度等级：
　　0或LOW：只检查长度；
　　1或MEDIUM：检查长度，数字，大小写，特殊字符；
　　2或STRONG：检查长度，数字，大小写，特殊字符和文件

1 mysql> SET GLOBAL validate_password_length=4;　　　　  #修改密码最小长度为4
2 mysql> SET GLOBAL validate_password_policy=LOW;　　　　#修改检查强度为LOW
3 mysql> FLUSH PRIVILEGES;　　　　　　　　　　      　　　  

1 mysql>  SHOW VARIABLES LIKE ‘validate_password%‘;

+--------------------------------------+-------+
| Variable_name                        | Value |
+--------------------------------------+-------+
| validate_password_check_user_name    | OFF   |
| validate_password_dictionary_file    |       |
| validate_password_length             | 4     |
| validate_password_mixed_case_count   | 1     |
| validate_password_number_count       | 1     |
| validate_password_policy             | LOW   |
| validate_password_special_char_count | 1     |
+--------------------------------------+-------+
7 rows in set (0.00 sec)

1 mysql> ALTER USER ‘root‘@‘localhost‘ IDENTIFIED BY ‘root123‘;
2 mysql> FLUSH PRIVILEGES;

1 mysql> use mysql
2 mysql> SELECT user,host FROM user WHERE user=‘root‘;

+------+-----------+
| user | host      |
+------+-----------+
| root | localhost |　　　　#只允许本机登录
+------+-----------+
1 row in set (0.00 sec)

1 mysql> UPDATE user SET host=‘%‘ WHERE user=‘root‘;
2 mysql> SELECT user,host FROM user WHERE user=‘root‘;

+------+------+
| user | host |
+------+------+
| root | %    |　　　　
+------+------+
1 row in set (0.00 sec)

1 mysql> GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘%‘ IDENTIFIED BY ‘root123‘ WITH GRANT OPTION; 　　　　#授权
2 mysql> FLUSH PRIVILEGES;