PHP Help Inner Join issue mysqli

Question

i need to show support tickets from the table tickets against user_id from users table. I'm using MySQLI. Here is the query that i have written and that is not working for me:

SELECT user_id, subject, message FROM tickets 
INNER JOIN users.user_id WHERE user_id='".$user_id."'"

Can anyone please correct this query?

Full code here

<?php
$servername = "localhost";
$username = "d";
$password = "ddds";
$dbname = "sddd";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT user_id, subject, message FROM tickets INNER JOIN users.user_id USING (user_id) WHERE user_id='".$user_id."'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    echo "<table class='table table-bordered'>
         <thead>
            <tr>                                                
              <th>Subject</th>
              <th>Date</th>
              <th>Status</th>
              <th>View</th>
            </tr>
           </thead>";
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "<tr><td>".$row["subject"]."</td><td>".$row["date"]." ".$row["status"]."</td><td>".$row["view"]."</td></tr>";
    }
    echo "</table>";
} else {
    echo "0 results";
}
$conn->close();
?> 

Answer 1

Corrected syntax:

SELECT T.user_id, T.subject, message FROM tickets T 
INNER JOIN users U ON U.user_id = T.user_id WHERE `T.user_id='".$user_id."'"`

You have forgot ON .

Answer 2

If you want to use INNER JOIN you have to specify where you are making a join (using on or using ) like these fallowing queries :

SELECT user_id, subject, message 
FROM tickets 
INNER JOIN users.user_id ON tickets.user_id = users.user_id 
WHERE user_id = '".$user_id."'"

OR

SELECT user_id, subject, message 
FROM tickets 
INNER JOIN users.user_id USING (user_id) 
WHERE user_id = '".$user_id."'" 

Answer 3

you should join only tables and not fields!

SELECT user_id, subject, message FROM tickets 
INNER JOIN users.user_id WHERE user_id='".$user_id."'"

join tickets table to users.user_id that is a field of users table. Should be:

SELECT user_id, subject, message FROM tickets 
INNER JOIN users USING (user_id) WHERE user_id='".$user_id."'"

You can also use ON to do the join (using is a shortcut when the colum names match):

SELECT user_id, subject, message FROM tickets 
INNER JOIN users ON tickets.user_id=users.user_id WHERE user_id='".$user_id."'"