地址， https://dev.mysql.com/downloads/mysql/ ， 选择版本 mysql-5.7.28-1.el6.x86_64.rpm-bundle.tar 。 我下载的是 bundle ，各个文件全包括在内了。
检查linux是否已经有自带的mysql，如果有，删除掉。
rpm -qa | grep mysql
rpm -qa | grep mysql | xargs rpm -e --nodeps
解压bundle.tar 文件， 执行 rpm -ivh 命令安装 。如果过程中，碰到缺库问题，根据名字手动安装即可。
service mysqld start
使用 mysql -u root -p 登录，提示要密码。在 /var/log/mysql.log 找到初始的密码。
cat /var/log/mysqld.log | grep password
再次登录即可。
按照提示 必须要用 ALTER USER 的语法。
mysql> ALTER USER USER() IDENTIFIED BY ‘Root1234@Root‘;
Query OK, 0 rows affected (0.00 sec)
查看密码的设置要求。
mysql> SHOW VARIABLES LIKE ‘vali%‘;
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password_check_user_name | OFF |
| 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 |
+--------------------------------------+--------+
7 rows in set (0.01 sec)
自定义以上要求，降低密码的复杂度。
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_special_char_count = 0
-> ;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=4
-> ;
Query OK, 0 rows affected (0.01 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>
mysql>
mysql> show tables;
+---------------------------+
| Tables_in_mysql |
+---------------------------+
| columns_priv |
| db |
| engine_cost |
| event |
| func |
| general_log |
| gtid_executed |
| help_category |
| help_keyword |
| help_relation |
| help_topic |
| innodb_index_stats |
| innodb_table_stats |
| ndb_binlog_index |
| plugin |
| proc |
| procs_priv |
| proxies_priv |
| server_cost |
| servers |
| slave_master_info |
| slave_relay_log_info |
| slave_worker_info |
| slow_log |
| tables_priv |
| time_zone |
| time_zone_leap_second |
| time_zone_name |
| time_zone_transition |
| time_zone_transition_type |
| user |
+---------------------------+
31 rows in set (0.00 sec)
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 | |
| 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 | |
| Grant_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| References_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Index_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Alter_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Show_db_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Super_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Create_tmp_table_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Lock_tables_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Execute_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Repl_slave_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Repl_client_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Create_view_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Show_view_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Create_routine_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Alter_routine_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Create_user_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Event_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Trigger_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| Create_tablespace_priv | enum(‘N‘,‘Y‘) | NO | | N | |
| ssl_type | enum(‘‘,‘ANY‘,‘X509‘,‘SPECIFIED‘) | NO | | | |
| ssl_cipher | blob | NO | | NULL | |
| x509_issuer | blob | NO | | NULL | |
| x509_subject | blob | NO | | NULL | |
| max_questions | int(11) unsigned | NO | | 0 | |
| max_updates | int(11) unsigned | NO | | 0 | |
| max_connections | int(11) unsigned | NO | | 0 | |
| max_user_connections | int(11) unsigned | NO | | 0 | |
| plugin | char(64) | NO | | mysql_native_password | |
| authentication_string | text | YES | | NULL | |
| password_expired | enum(‘N‘,‘Y‘) | NO | | N | |
| password_last_changed | timestamp | YES | | NULL | |
| password_lifetime | smallint(5) unsigned | YES | | NULL | |
| account_locked | enum(‘N‘,‘Y‘) | NO | | N | |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
45 rows in set (0.00 sec)
mysql> select Host,User,authentication_string from user;
+-----------+---------------+-------------------------------------------+
| Host | User | authentication_string |
+-----------+---------------+-------------------------------------------+
| localhost | root | *1E0532C5DAF747138FB6C69FE370B6213B6EE5E4 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+-----------+---------------+-------------------------------------------+
3 rows in set (0.00 sec)
mysql> update user set authentication_string=PASSWORD(‘root123‘) where User=‘root‘;
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> select Host,User,authentication_string from user;
+-----------+---------------+-------------------------------------------+
| Host | User | authentication_string |
+-----------+---------------+-------------------------------------------+
| % | root | *FAAFFE644E901CFAFAEC7562415E5FAEC243B8B2 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
+-----------+---------------+-------------------------------------------+
3 rows in set (0.00 sec)
到这里， 修改密码完成。
原文：https://www.cnblogs.com/wuyicode/p/11913866.html