ubuntu系统xampp环境下，mysql的root账号权限丢失，即root账号没有任何database的访问权限，mysql>show databases 只显示information_schema和test。
解决方法：进入mysql安全模式，修改root权限。
首先关闭mysql服务 /opt/lampp/lampp stop
进入安全模式：
打开一个命令行终端：/opt/lampp/sbin/mysqld --skip-grant-tables (该命令行终端不要关闭)
打开另一个命令行终端：mysql -u root
修改root权限：
use mysql;
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';
最好更新下密码，最后刷新下权限
update user set Password=password('newPassword') where user="root";
flush privileges;
关闭第一个打开安全模式的终端，启动lampp：/opt/lampp/lampp start。结束。
Mysql权限不足问题解决方案：http://www.linuxdiyf.com/linux/17210.html