vim /etc/my.cnf文件；
在[mysqld]后添加skip-grant-tables（登錄時跳過權限檢查）
重啟MySQL服務：sudo systemctl restart mysqld
登錄mysql，輸入mysql –uroot –p；直接回車（Enter）
輸入：set password for 'root'@'localhost'=password('admin');
如果報：ERROR 1290 (HY000): The MySQL?server?is running with the --skip-grant-tables option so it cannot execute this statement
輸入：flush privileges;
再次輸入：set password for ‘root’@‘localhost’=password(‘Admin123@qwe’);
為避免麻煩，再次設置遠程訪問
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY 'Admin123@qwe' WITH GRANT OPTION;
flush privileges;
退出：exit
再把my.ini的skip-grant-tables刪除或者注釋掉
重啟MySQL：sudo systemctl restart mysqld
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