Question

I am having issues with the

<?php
//create_cat.php
include 'connect.php';
include 'header.php';

$sql = "SELECT
            topic_id,
            topic_subject,
            topic_cat
        FROM
            topics
        WHERE
            topics.topic_id = " . mysql_real_escape_string($_GET['id']);

$result = mysql_query($sql);
$row = mysql_fetch_assoc($result);

echo '<a href="index.php">Nexus</a> > <a href="category.php?id=' . $row['topic_cat'] . '">Category will go here.</a> > <a href="topic.php?id=' . $row['topic_id'] . '">' . $row['topic_subject'] . '</a><br>';

if(!$result)
{
    echo 'The topic could not be displayed, please try again later.';
}
else
{
    if(mysql_num_rows($result) == 0)
    {
        echo 'This topic doesn&prime;t exist.';
    }
    else
    {

        {
            //display post data
            echo '<table class="topic">
                    <tr>
                        <th colspan="2">' . $row['topic_subject'] . '</th>
                    </tr>';

            //fetch the posts from the database
            $posts_sql = "SELECT
                        posts.post_topic,
                        posts.post_content,
                        posts.post_date,
                        posts.post_by,
                        posts.post_id,
                        users.user_id,
                        users.user_name,
                        users.user_title,
                    FROM
                        posts
                    LEFT JOIN
                        users
                    ON
                        posts.post_by = users.user_id
                    WHERE
                        posts.post_topic = " . mysql_real_escape_string($_GET['id']);

            $posts_result = mysql_query($posts_sql);

            if(!$posts_result)
            {
                echo '<tr><td>The posts could not be displayed, please try again later.</tr></td></table>';
            }
            else
            {
                while($posts_row = mysql_fetch_assoc($posts_result))
                {
                    echo '<tr class="topic-post">

                            <td class="user-post"><div id="user">
                                <b>' . $posts_row['user_name'] . '</b><br/>' . $posts_row['user_title'] . '</div><br/>' . date('m-d-Y h:ia', strtotime($posts_row['post_date'])) . '</td>
                            <td class="post-content">
                            <a name="postid=' . $posts_row['post_id'] . '"></a>
                            ' . htmlentities(stripslashes($posts_row['post_content'])) . '</td>
                          </tr>';
                }
            }

            if(!$_SESSION['signed_in'])
            {
                echo '<tr><td colspan=2>You must be <a href="signin.php">signed in</a> to reply. You can also <a href="signup.php">sign up</a> for an account.';
            }
            else
            {
                //show reply box
                echo '<tr><td colspan="2"><h2>Reply:</h2><br />
                    <form method="post" action="reply.php?id=' . $row['topic_id'] . '">
                        <textarea name="reply-content"></textarea><br /><br />
                        <input id="button" type="submit" value="Submit reply" />
                    </form></td></tr>';
            }

            //finish the table
            echo '</table>';
        }
    }
}

include 'footer.php';
?>

It says

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘FROM posts LEFT JOIN users ON posts.post_by = u’ at line 10

at the bottom (I added an echo mysql_error(); at the bottom). This is rather important as it is for forum software that other people actually use and it powers about 4 different things on my site (seems excessive, but all are temporarily hooked up to the same database, one is for active development of it, and the other is for the actual software).

Answer 1

you have extra comma before the from clause to remove,

SELECT
        posts.post_topic,
        posts.post_content,
        posts.post_date,
        posts.post_by,
        posts.post_id,
        users.user_id,
        users.user_name,
        users.user_title   // << remove extra comma here
FROM
        posts
LEFT JOIN
        users
ON
        posts.post_by = users.user_id