Question

I am using this script to read a value in a session, then I want to query the database about this value :

    <?php
session_start();
$user_id = $_SESSION["user_id"] ;
echo "Your user_id is: $user_id \n" ;

$query = sprintf("SELECT * FROM `customers` WHERE id='%s' ", $user_id);
$result = mysql_query($query);

if (!$result) {
    $message  = 'Invalid query: ' . mysql_error() . "\n";
    $message .= 'Whole query: ' . $query;
    die($message);
}

while ($row = mysql_fetch_assoc($result)) {
    $email =  $row['email'] . "\n";
    echo "Your e-mail adress is : $email \n" ;
}
?>

I get this when I test the page with my browser:
Your user_id is: 1430

Invalid query: Access denied for user ‘nobody’@’localhost’ (using password: NO) Whole query: SELECT * FROM customers WHERE id=’1430′

Thanks a lot!

Answer 1

Connect to your database server first and select a database using mysql_connect and mysql_select_db. The mysql_query function will try to open a connection with default parameters, or as the manual puts it:

If no such link is found, it will try to create one as if mysql_connect() was called with no arguments.

Hence, PHP is trying to connect to localhost with username "nobody" and no password.

mysql_connect('localhost', 'mysql_user', 'mysql_password');
mysql_select_db('my_database');

..and you’re ready to go.