Selecting specific data using table joins - php

Question

I am attempting to output some a user username from the user table by joining it from a questions table, the intention being I can show which user posted this specific question.
users with id, username
discussion_q id, question_text, user_id
Here is where I am at:
$sql = "SELECT q.id AS questionId, q.question_text AS questionText, q.user_id AS questionUserId, q.published AS questionPub, users.id AS userId
FROM discussion_q
JOIN users
ON questionUserId = userId
WHERE project_id = '$projectId'
ORDER BY published";
I am getting 0 results returned back to me of course. I am sure I have over engineered this or missed something simple?
Here is my php to return the results:
$result = $conn->query($sql);
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_assoc($result)) {
echo '<div class="twelve columns">
<p>' . $row['question_text'] . '</p>
<p>' . $row['published'] . ' by ' . $row['username'] . '</p>
</div>';
}
} else {
echo "0 results";
}
So the end goal is to output the question_text with the username of the user who posted.

Answer 1

$sql = "SELECT q.id AS questionId, q.question_text AS questionText, q.user_id AS questionUserId, q.published AS questionPub, users.id AS userId
FROM discussion AS q
JOIN users
ON (q.user_id = users.id)
WHERE project_id = '$projectId'
ORDER BY published";