转自：https://www.cnblogs.com/benjamin77/p/8681763.html
如题所述，mysql5.7 mysql库下面的user表没有password字段无法修改密码，
5.7版本已经不再使用password来作为密码的字段了 而改成了authentication_string
登陆密码记不起：
[root@master1 ~]# mysql -uroot -p Enter password: ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
更改配置
vi /etc/my.cnf #在mysqld模块下添加 skip-grant-tables
重启服务
systemctl restart mysqld
按照传统改密码方式发现没有 password这个字段。
mysql> update user set password=password('123') where user='root';
ERROR 1054 (42S22): Unknown column 'password' in 'field list'
查询user表结构
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 | |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
网上查了一下据说5.7 版本password 字段改成authentication_string password函数还是原来的password函数
mysql> update user set authentication_string=password('123') where user='root';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1
#更改配置重启mysql 成功登陆
[root@master1 ~]# vi /etc/my.cnf
注释 # skip-grant-tables [root@master1 ~]# systemctl restart mysqld [root@master1 ~]# mysql -uroot -p123 mysql: [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 2 Server version: 5.7.21-log Copyright (c) 2000, 2018, 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>