解決方法：1、在my.cnf中，增加「[mysqld]」和「skip-grant-tables」2行程式碼，用於登入時跳過密碼驗證；2、啟動mysql服務，並登入mysql；3、連接mysql資料庫，使用UPDATE指令修改使用者密碼即可。
（推薦教學：mysql影片教學）
修改密碼
#1. 檢查mysql服務是否啟動，如果啟動，關閉mysql服務
//查看mysql服务状态 [root@mytestlnx02 ~]# ps -ef | grep -i mysql root 22972 1 0 14:18 pts/0 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --pid-file=/var/run/mysqld/mysqld.pid --basedir=/usr --user=mysql mysql 23166 22972 0 14:18 pts/0 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/lib/mysql/mysql.sock root 23237 21825 0 14:22 pts/0 00:00:00 grep -i mysql //关闭服务 [root@mytestlnx02 ~]# service mysql stop [root@mytestlnx02 ~]#
2.修改mysql的設定檔my.cnf
my.cnf設定檔的位置，一般在/etc/my.cnf，有些版本在/etc/mysql/my.cnf
#在設定檔中，增加2行程式碼
[mysqld] skip-grant-tables
作用是登入mysql的時候跳過密碼驗證
然後啟動mysql服務，並進入mysql
[root@mytestlnx02 ~]# service mysqld start [root@mytestlnx02 ~]# [root@mytestlnx02 ~]# mysql -u root Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>
3.修改密碼
連接mysql這個資料庫，修改使用者密碼
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> update mysql.user set authentication_string=password('root_password') where user='root';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> exit4. 重啟mysql服務
#先將之前加在設定檔裡面的2句程式碼註解或刪除掉，然後重啟mysql服務，就可以使用剛剛設定的密碼登入了。
[root@mytestlnx02 ~]# service mysql start [root@mytestlnx02 ~]# [root@mytestlnx02 ~]# mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g.
p.s.
在CentOS上的操作方式有所不同。
執行修改密碼的指令一直報錯
mysql> update user set authentication_string=password('xxxxxxxx') where User='root';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('root_password') where User='root'' at line 1不可能是文法問題，檢查了很多遍，最後發現CentOS下應該這樣操作：
查看初始密碼
[root@VM_0_8_centos ~]# grep 'temporary password' /var/log/mysqld.log 2018-09-26T04:25:54.927944Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: DN34N/=?aIfZ
可以看到初始密碼為DN34N/=?aIfZ
使用初始密碼登入
#
[root@VM_0_8_centos ~]# mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 8 Server version: 8.0.12 MySQL Community Server - GPL Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
mysql> ALTER USER 'root' IDENTIFIED BY 'xxxxxxxxx'; ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement. mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'xxxxxxxx'; Query OK, 0 rows affected (0.11 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec) mysql> exit Bye
[root@VM_0_8_centos ~]# service mysqld stop Redirecting to /bin/systemctl stop mysqld.service [root@VM_0_8_centos ~]# service mysqld start Redirecting to /bin/systemctl start mysqld.service
以上是linux上mysql改密碼忘了怎麼辦？的詳細內容。更多資訊請關注PHP中文網其他相關文章！
