无法获取表单发布或查询不起作用

Question

I'm trying to learn about $_SESSION variables and I've been following some tutorials I've found online. I've created a form and I'm posting it back to the same page but the query fails. I have a table 'users' and I've added 'bob' to the userlogin field and 'bob' to the user_passwrd field. When I execute I get the error from the if/else statement that the query failed. I don't know what I'm doing wrong and I would really appreciate some help on this. I don't know if the form is not posting or where the problem might be. Here is the code:

<?php
    include ('admin_pages/sql_pages/sql_connect_L.inc.php');

    $login = mysql_real_escape_string($_POST['login']);
    $passwrd = mysql_real_escape_string($_POST['passwrd']);

    $sql = mysql_query("SELECT * FROM users WHERE userlogin = '$login' AND user_passwrd = '$passwrd'");

    $count = mysql_num_rows($sql);

    if($count == 1)
    {
        session_start();
        $_SESSION['login'] = '$login';
        header('location: admin_pages/dashboard.php');
    }

    else
    {
        echo " Your query failed";
    }

?>

    <form method="post" action="logintest.php">
      Username: <input name="login" type="text" class="login_fields" />
      <br/>
      Password: <input name="passwrd" type="password" class="login_fields" />
      <br/>
      <input name="submit" type="submit" class="long_button" id="submit" value="Login" />
    </form>

I've tried several different things and I can't get the desired results.

Cheers

Answer 1

The first step in debugging is, check your SQL string:

$sqlText = "SELECT * FROM users WHERE userlogin = '$login' AND user_passwrd = '$passwrd'";
echo $sqlText;
$sql = mysql_query($sqlText) or die(mysql_error());

I noticed, you have minor issue in your code:

$_SESSION['login'] = '$login';

will result in $_SESSION['login'] having value of $login literally. Not the value of $login. To fix it, change your code into:

$_SESSION['login'] = "$login";
//or to be simpler:
$_SESSION['login'] = $login;

Why is that? here's the explanations.