mysql5.7 誤刪管理員root帳戶

1.中止數據庫，並在mysql配置文件my.cnf中添加skip-grant-tables參數到[mysqld]配置塊中

2. 執行 systemctl start mysqld

3. 執行 mysql 

4.建立 root 用戶並賦權限，並修改root密碼

insert into user set user='root',ssl_cipher='',x509_issuer='',x509_subject='';

update user set Host='localhost',select_priv='y', insert_priv='y',update_priv='y', Alter_priv='y',delete_priv='y',create_priv='y',drop_priv='y',reload_priv='y',shutdown_priv='y',Process_priv='y',file_priv='y',grant_priv='y',References_priv='y',index_priv='y',create_user_priv='y',show_db_priv='y',super_priv='y',create_tmp_table_priv='y',Lock_tables_priv='y',execute_priv='y',repl_slave_priv='y',repl_client_priv='y',create_view_priv='y',show_view_priv='y',create_routine_priv='y',alter_routine_priv='y',create_user_priv='y' where user='root';

update user set authentication_string=password('123456') where user='root';

5. 刷新 退出mysql

flush privileges;
quit

6.註釋掉skip-grant-tables參數，重啓數據庫