PHP:mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in [file] on line 13

Question

i have this error mentioned in the title with this code:

    <?php  session_start(); 
       ob_start();

                include("connection.php");

                $username = $_POST['username'];
                $password = $_POST['password'];

                $query = mysql_query("SELECT * FROM users WHERE user_username = '$username' AND user_password = '$password'",$conn)
                or die($query. "<br/><br/>".mysql_error());

                if($query = mysql_affected_rows() > 0) {
                    $record = mysql_fetch_assoc($query);
                    $validuser = $row['username'];
                    $_SESSION['valid'] = $validuser;
                    if(isset($_SESSION['valid']))
                    {
                        header('Location:  index.php');         
                    }
                    } else { ?>
                        <script>alert('Username not registered.')
                        </script>
<?php
                   }
                    exit();

?>

this is my web assignment and im a newbie in php. please need help.

Here's a tip: `mysql_affected_rows` only works for INSERT, UPDATE, REPLACE or DELETE. You need `mysql_num_rows`. — Burhan Khalid, Oct 20 '13 at 08:04

Amal Murali · Accepted Answer · 2013-10-20T08:11:10.460

You have the following in your code:

if($query = mysql_affected_rows() > 0) {

mysql_affected_rows() returns the number of affected rows. If it's greater than 0, then $query will be TRUE, and if not, it will be FALSE. The value of $query will always be a boolean value.

mysql_fetch_assoc() expects a MySQL resource as it's parameter but you'll be passing a boolean value instead. That's the cause of the error.

From the documentation for mysql_affected_rows():

Get the number of affected rows by the last INSERT, UPDATE, REPLACE or DELETE query associated with link_identifier.

Another thing is that you're running a SELECT statement, you probably want mysql_num_rows() instead.

Normally, your if statement should look like:

if(mysql_num_rows($query) > 0) {
    # code ...
}

You can adjust it with your code as follows:

$num = mysql_num_rows($query);

if($num > 0) 
{
    while ($record = mysql_fetch_assoc($query)) 
    {
        $validuser = $row['username'];
        $_SESSION['valid'] = $validuser;
        if(isset($_SESSION['valid']))
        {
            header('Location:  index.php');         
        }
    }
}
else 
{
    # else block ...
}

Also, note that mysql_ functions are deprecated and are soon to be removed. You should switch to MySQLi or PDO and start using parameterized queries to be safe.

thanks man you made my day! – DeadLuck Oct 20 '13 at 08:30 — DeadLuck, Oct 20 '13 at 08:30
@user2467945: You're welcome :) – Amal Murali Oct 20 '13 at 08:31 — Amal Murali, Oct 20 '13 at 08:31

score 0 · Answer 2 · answered Oct 20 '13 at 07:54

0

In this loop:

if($query = mysql_affected_rows() > 0)

You are assigning $query to the result of the expression. So $query will either be True or False.

Then in the loop, you are doing:

$record = mysql_fetch_assoc($query);

This is where the error gets triggered, since now $query is no longer the result of the mysql_query method.

To fix this, change your if condition:

if(mysql_affected_rows() > 0)

You should also upgrade your code because the old mysql_* functions will be removed from PHP.

answered Oct 20 '13 at 07:54

Burhan Khalid

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In PHP, the mysql_query call executes the query immediately (its not set to a transaction that needs to be committed). You are right about the second point though; which should be another question from the OP (eventually). – Burhan Khalid Oct 20 '13 at 08:03

score 0 · Answer 3 · answered Oct 20 '13 at 08:23

change this code :

if($query = mysql_affected_rows() > 0) {
                    $record = mysql_fetch_assoc($query);
                    $validuser = $row['username'];

to this :

 if(mysql_num_rows($query) > 0) {
                $record = mysql_fetch_assoc($query);
                $validuser = $record['username'];

PHP:mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in [file] on line 13

3 Answers3