mysql错误：Ignoring query to other database

进入mysql使用命令的时候总是提示：Ignoring query to other database，mysql没有做任何修改，刚刚还使用好好的，怎么就突然这样了，而且还是正式的环境就查看个数据没有做其他的呀。郁闷，从新查看一下命令：

[root@wulaoer ~]# mysql -root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 5.6.49 MySQL Community Server (GPL)

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Oracle is a registered trademark of Oracle Corporation and/or its
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owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
Ignoring query to other database

原来我在敲命令的时候没有制定-u，意思就是用户。这个错误虽然不是什么大的错误，不过值得记一下。