help needed with me log on script

[pravin_fer]

hello folks i am new to php
i have created a log on script to check userid and password from mysql database, but even if i enter correct uesrname and password it doesnt display correct message
plse help me

<?php
                                                                                 
    include 'database_connect.private'; 
?>


<?php

$pid=$_POST["UserID"];
$passwrd=$_POST["PassWord"];
//$flag=false;

error_reporting(1);
session_start();
header("Cache-control: private");

$connection = mysql_connect($hostname,$username,$password);
      mysql_select_db($databaseName, $connection);
     
/* $result = mysql_query ("SELECT * FROM staff", $connection);


while ($row = mysql_fetch_row($result))
{
echo "hello";
if($pid==$row[0] && $passwrd==$row[1])
{echo "hello";
    $flag=true;

    }
  }*/

  //if(isset($_POST['submit'])
//{
$query="SELECT * FROM staff WHERE staff_Id ='$pid' AND password='$passwrd' ";
$result=mysql_query($query);
//or die(mysql_error());
echo "try";

if (mysql_num_rows($result)==1)
{
echo "user logged in";
$_SESSION['user_logged']=$_POST['user_Id'];
$_SESSION['user_password']=$_POST['password'];
echo "Successful login ... Click Here to ";
//redirect ("http://stuweb.cms.gre.ac.uk/~fj330/home.html")
}
else
{
echo "<p> Sorry Unauthorized Access is not Allowed</p>";

}



//mysql_close($connection);

?>

[ToonMariner]

test your query in phpmyadmin or similar and see what is returned...
(echo out your query string before you run the query - then you can copy and paste into your favorite db app!)