Trying to echo a table but it's not working - mysql

Question

The table is called bookings. I'm trying to echo rows from the table, but I'm getting errors in some places according to user_id. Dreamweaver tells me the last few lines have errors, but I'm not sure what's the problem.
<?php
require 'connect.php';
include("auth.php");
$user = $_SESSION['username'];
$uid = $_SESSION['user_id'];
$sql = "SELECT * FROM bookings WHERE user_id =". $uid;
$result = mysqli_query($conn, $sql);
if ($result->num_rows > 0) { // if the mysqli_query performed above works
echo "<br>";
echo '<table border="1">';
echo '<tr>
<th>booking_id</th>
<th>"Room_name"</th>
<th>"booking_date"</th>
<th>"period_name"</th>
<th>"booking_id"</th>
<th>"Cancel Booking"</th>
</tr>';
while ($row = mysqli_fetch_assoc($result)) { // important line
echo '<tr>';
echo '<td>'.$row["booking_id"].'</td>';
echo '<td>'.$row["Room_name"].'</td>';
echo '<td>'.$row["booking_date"].'</td>';
echo '<td>'.$row["date_booked"].'</td>';
echo '<td>'.$row["period_name"].'</td>';
echo '<td>'.$row["booking_id"].'</td>';
echo "</tr>";
echo "</table>";
}
else echo '<p>You have no bookings.</p>';

Answer 1

I have made some change
And here is the code-
require 'connect.php';
include 'auth.php';
$user = $_SESSION['username'];
$uid = $_SESSION['user_id'];
$sql = "SELECT * FROM bookings WHERE user_id ='". $uid."'";
$result = mysqli_query($conn, $sql);
if ($result->num_rows > 0) { // if the mysqli_query performed above works
echo "<br>";
echo '<table border="1">';
echo '<tr>
<th>booking_id</th>
<th>Room_name</th>
<th>booking_date</th>
<th>period_name</th>
<th>booking_id</th>
<th>Cancel Booking</th>
</tr>';
while ($row = mysqli_fetch_assoc($result)) { // important line
echo '<tr>';
echo '<td>'.$row["booking_id"].'</td>';
echo '<td>'.$row["Room_name"].'</td>';
echo '<td>'.$row["booking_date"].'</td>';
echo '<td>'.$row["date_booked"].'</td>';
echo '<td>'.$row["period_name"].'</td>';
echo '<td>'.$row["booking_id"].'</td>';
echo '</tr>';
}
echo '</table>';
} else echo '<p>You have no bookings</p>';