问题现象：
[root@zxdb05 ~]# mysql -root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 5
Server version: 5.6.25-log MySQL Community Server (GPL)
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> show databases;
Ignoring query to other database
问题分析：
查看错误日志，并无错误记录信息；
后来发现原来是连接的时候少写了u参数。
[root@zxdb05 ~]# mysql -root –p
改成：[root@zxdb05 ~]# mysql -uroot –p
少写了参数居然能够连接成功，但不能进行操作，非常不人性化的设计