今天同事，调整mysql安全，在删除用户的时候误删了 root@localhost，后来加进去了，但是在登录发现数据库很多库都没有了，顿时懵逼，考虑恢复数据，稍后我看到了，想起当年也出现过类似情况，主要是因为root用户没有权限，所以跳过授权表，经过查询权限，真的缺少，所以将其都由N改为Y ，在次测试，OK，以下是处理步骤。
第一步，跳过授权表登录mysql
1、pkill 停止 实例进程 2、mysqld_safe --defaults-file=/data/3306/my.cnf --skip-grant-tables & 3、mysql -S /data/3306/mysql.sock 4、UPDATE mysql.user SET password=PASSWORD('oldboy123') WHERE user='root' and host='localhost'; 5、flush privileges; 6、kill掉mysqld_safe 进程 7、/etc/init.d/msyql start 正常启动 登录即可 mysql -uroot -poldboy123第二步、修改权限（也可以初始化root密码）
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> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | oldboy_gbk | | performance_schema | | qiuyuetao | | test | +--------------------+ 6 rows in set (0.00 sec) mysql> show tables; +---------------------------+ | Tables_in_mysql | +---------------------------+ | columns_priv | | db | | event | | func | | general_log | | help_category | | help_keyword | | help_relation | | help_topic | | host | | ndb_binlog_index | | plugin | | proc | | procs_priv | | proxies_priv | | servers | | slow_log | | tables_priv | | time_zone | | time_zone_leap_second | | time_zone_name | | time_zone_transition | | time_zone_transition_type | | user | +---------------------------+ 24 rows in set (0.00 sec) 更新的MYSQL.USER表的所有字段中为Ｎ的为Ｙ就可以了。 update user set Select_priv ='Y' where user = 'root'; update user set Insert_priv ='Y' where user = 'root'; update user set Update_priv ='Y' where user = 'root'; update user set Delete_priv ='Y' where user = 'root'; update user set Create_priv ='Y' where user = 'root'; update user set Drop_priv ='Y' where user = 'root'; update user set Reload_priv ='Y' where user = 'root'; update user set Shutdown_priv ='Y' where user = 'root'; update user set Process_priv ='Y' where user = 'root'; update user set File_priv ='Y' where user = 'root'; update user set Grant_priv ='Y' where user = 'root'; update user set References_priv ='Y' where user = 'root'; update user set Index_priv ='Y' where user = 'root'; update user set Alter_priv ='Y' where user = 'root'; update user set Show_db_priv ='Y' where user = 'root'; update user set Super_priv ='Y' where user = 'root'; update user set Create_tmp_table_priv ='Y' where user = 'root'; update user set Lock_tables_priv ='Y' where user = 'root'; update user set Execute_priv ='Y' where user = 'root'; update user set Repl_slave_priv ='Y' where user = 'root'; update user set Repl_client_priv ='Y' where user = 'root'; update user set Create_view_priv ='Y' where user = 'root'; update user set Show_view_priv ='Y' where user = 'root'; update user set Create_routine_priv ='Y' where user = 'root'; update user set Alter_routine_priv ='Y' where user = 'root'; update user set Create_user_priv ='Y' where user = 'root'; update user set Event_priv ='Y' where user = 'root'; update user set Trigger_priv ='Y' where user = 'root';另外有需要云服务器可以了解下创新互联cdcxhl.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。
