sql syntax using sprintf

until i started using the techniques for avoiding sql injection, i have been using a normal insert and select sql query which worked fine. i have a registration page where a user enters their username and if this already exists i display a message by executing a select query and if the username does not exist then i run an insert query. after adopting the technique to avoid sql injection if(get_magic_quotes_gpc()) { $username = stripslashes($_POST["username"]); $email = stripslashes($_POST["email"]); } else { $username = $_POST["username"]; $email = $_POST["email"]; } previously my select and insert query were INSERT INTO individuals(username, email) values('$username', '$email') Select username from individuals where username = '$username' presently the insert query is $insertquery = sprintf("INSERT INTO individuals (username, email) VALUES ('%s', '%s')", mysql_real_escape_string($username), mysql_real_escape_string($email)); This insert query is working however the select query is not doing its task as before of checking if the username already exists or not, even if i register with the same username again it does not alert that the username exists. the select query is $selectqueryusername = sprintf("Select username from individuals where username='%s'", mysql_real_escape_string($username)); should i change the syntax of the above select query or is there something else in need to do to fix the select query. please advice. thanks.