need to search mysql for something and return the value in the next colum

Question

Hi all, 

i have a very simple table in mysql, i can connect etc fine, and i think i have the query i need, but how do i get this working in c#?

what it will basically do is find a username based on the windows username.

sUserName = Environment.UserName;

"'select sms_un from smsusers where domain_un = ' + sUserName;";

sorry its quite hard to describe :) does this make sense?