Question: ```
mysql -uroot -proot

```

This is the error I get:

> 
> mysql: [Warning] Using a password on the command line interface can be
>  insecure. ERROR 1698 (28000): Access denied for user
>  'root'@'localhost'
> 
> 
>

Answer: 
I guess it depends of your 'image'.
If you are connecting via SSH you can also try to login without a password

```
mysql -u root

```

I am using scotch-box vagrant image and works for me (note that the connections made by my php scripts requires the root user password).
Try using the wamp server to connect to mysql.