PHP PDO更新语句失败

The below sql UPDATE statement returns an error but I'm unable to see why:

Failed to run query: SQLSTATE[42000]: Syntax error or access violation: 1064 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 ')' at line 6

I already did a vardump of the array that I pass to bind the parameters but I see nothing unusual. The correct values are passed and I double checked for typos. What I try to accomplish is to auto-generate a username based on firstname - lastname and user_id after insertion into the database.
Perhaps additional question: do you see any harm in that and if so, what is your suggestion? I'm still in PHP learning phase.

Thanks.

        ...

        //Autogenerate user_name based on first name, last name and user_id (auto-increment) 
        $query_username = "
            UPDATE user_tbl 
                SET
                    user_name = :username 
                WHERE
                    user_id = :userid
            ) 
        ";

        // The parameter values 
        $query_params_username = array(
            ':username' => $_SESSION['user']['first_name'].".".$_SESSION['user']['last_name'].$_SESSION['user']['user_id'],
            ':userid' => $_SESSION['user']['user_id']
        );

        try 
        { 
            // Execute the query against the database 
            $stmt_username = $db->prepare($query_username);
            $stmt_username->execute($query_params_username);
        }
        catch(PDOException $ex) 
        {       
             //Not to be used in production 
             die("Failed to run query: " . $ex->getMessage()); 
        }

        $_SESSION['user']['username'] = $_SESSION['user']['first_name'].".".$_SESSION['user']['last_name'].$_SESSION['user']['user_id'];

You had a closing parentheses after user_id = :userid

Try the following:

$query_username = "
    UPDATE user_tbl 
        SET
            user_name = :username 
        WHERE
            user_id = :userid
";

Try doing this:

$query_username = "
                     UPDATE  `user_tbl` 
                     SET     `user_name` = :username 
                     WHERE   `user_id` = :userid
                  ";

There seems to be a lost ) character in your code.