Error handling with a DB query

[ubunreal69]

i have a query checking my DB to see if a user exists (for my login script); i'm using the count(*) function in MySQL to display a '1' if the user exists but it cant return a '0' when it doesnt find anything, anyway, here is the code i am using:

mysql_result(mysql_query("SELECT *, count(*) FROM users 
WHERE uname='$u_name' AND upassword='$u_password' 
GROUP BY uname"),0,"count(*)"); 

Anyone know how to handle this error ?