a mysql question. thanks

I have two questions about the mysql (installed on unix),
1)I have input a wrong query, and the mysql window freezed, it keep running in the background and woun't accept any new queris. How can I terminate it safely without quiting the mysql?
2)I terminated a wrongly running query by type Ctrl-C, the mysql exit, but the mysqld is still running. I can use mysql as root, but I am just a regular user on the computer. How can I kill the mysqld and restart it?

Thank you very much in advance