Comparing hash causing issues - php

Question

I have a site that I am storing the username and hashed password in a table. I am trying to compair this information (username and hashed password) to the login information passed from my login site. Unfortunately this keeps crashing. If someone could point me in the right direction as to what I am doing wrong I would appreciate it. Below is the code I am using to check the login. It may be something very simple as I am still pretty new to php.
<?php
$myServer = "server.domain.com";
$myUser = "readaccess";
$myPass = "password";
$myDB = "database";
$dbhandle = mssql_connect($myServer, $myUser, $myPass)
or die("Couldn't connect to SQL Server on $myServer");
$selected = mssql_select_db($myDB, $dbhandle)
or die("Couldn't open database $myDB");
// username and password sent from form
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];
//declare the SQL statement that will query the database
$query = "SELECT password, salt ";
$query. = "FROM dbo.members ";
$query. = "WHERE username = '$myusername' ";
$result = mssql_query($query)
or die('A error occured: ' . mssql_get_last_message());
// SQL_num_row is counting table row
$count=mssql_num_rows($result);
if($count) < 1) //no such user exists
{
header('Location: main_login.php');
}
$userData = mssql_fetch_array($result, MSSQL_ASSOC);
$hash = hash('sha256', $userData['salt'] . hash('sha256', $mypassword) );
if($hash != $userData['password']) //incorrect password
{
header('Location: main_login.php');
}
else {
header('Location: index.php');
}
?>

Answer 1

I think the problem is this line
$result = mssql_query($query)
or die('A error occured: ' . mssql_get_last_message());
The proper way to check failure is
$result = mssql_query($query, $dbhandle);
if(!$result)
die('A error occured: ' . mssql_get_last_message());
Note that this goes for the mssql_connect and mssql_select_db statements as well.
Note that you need to provide the database resource to the mssql_query function.
Also, most people find it more readable if you use .= without a space between them. I don't think it produces a parse error, but it make a lot of sense to keep the whitespace out of the operand. (You wouldn't do $counter+ +; even if it were legal.)
Note for asking future questions, always include whatever error message you're seeing and, if it is referencing a line number, point out that line in your code sample. In this case, I don't think your problem has anything to do with hashing or sql, as it's entirely a parse/syntax error.