The majority of this code works just fine, the database get updated when I click on the button, but the last query (the UPDATE one) doesn't execute for some reason. I tried turning on mysql log on phpmyadmin, but even there it's not executed. It doesn't show me any error, and I really don't know what could be wrong.
$query = "SELECT username, coins FROM users WHERE userid='$userid' LIMIT 1";
$result = mysqli_query($db, $query);
$user = mysqli_fetch_assoc($result);
$_SESSION['username'] = $user['username'];
$_SESSION['coins'] = $user['coins'];
$op = $user['username'];
$op = mysqli_real_escape_string($forumdb, $op);
$postcontent = $_POST['postcontent'];
$postcontent = mysqli_real_escape_string($forumdb, $postcontent);
$posttitle = $_POST['posttitle'];
$posttitle = mysqli_real_escape_string($forumdb, $posttitle);
$sectionid = $_GET['sectionid'];
$sectionid = mysqli_real_escape_string($forumdb, $sectionid);
$query = "INSERT INTO topic (section_id, name, replies, op, lastpost, lastuserid, views, sticked) values('$sectionid', '$posttitle', '0','$op', CURRENT_TIMESTAMP(),'$userid', '0', '0')";
$result = mysqli_query($forumdb, $query) or trigger_error("Query Failed! SQL: $query - Error: ".mysqli_error($forumdb), E_USER_ERROR);
$last_id = mysqli_insert_id($forumdb);
$query = "INSERT INTO posts (topic_id, content, user_id) values('$last_id', '$postcontent', '$userid')";
mysqli_query($forumdb, $query);
$query = "UPDATE section SET lastpost='$username', threads=threads+1, posts=posts+1 WHERE id='$sectionid'";
mysqli_query($forumdb, $query) or trigger_error("Query Failed! SQL: $query - Error: ".mysqli_error($forumdb), E_USER_ERROR);