Can someone tell me why the query is not successful!!!

PHP Code:

<?php
$username = $_POST["username"];
$password = $_POST["password"];

$con = mysql_connect("localhost","root","blah");
if (!$con)
    {
    die('Could not connect: ' . mysql_error());
    }

mysql_select_db("test", $con);

$sql = "INSERT INTO names (username, password)
VALUES ("$username","$password")";

if (!mysql_query($sql,$con))
    {
    die('Error: ' . mysql_error());
    }
echo "1 record added";

mysql_close($con)
?>

What's the error message you're getting?

$sql = "INSERT INTO names (username, password)
VALUES ("$username","$password")";

change " by ' and try again ==> VALUES ('$username','$password')