PHP MySQL Warning: Illegal string offset 'title' - php

Question

I get this error:
Warning: Illegal string offset 'title' in C:\wamp64\www\Beep\php\config.php on line 33
When using this function:
function getComments() {
global $pdo;
$sql = "SELECT * FROM `comments`";
$stmt = $pdo->prepare($sql);
$stmt->execute();
$results = $stmt->fetch();
$comments = array();
foreach ($results as $result) {
array_push($comments, new Comment($result["title"], $result["content"], $result["author"]));
}
return $comments;}
class Comment {
var $title;
var $content;
var $author;
/**
* Comment constructor.
* #param $title
* #param $content
* #param $author
*/
public function __construct($title, $content, $author){
$this->title = $title;
$this->content = $content;
$this->author = $author;
}
}
Line 33 is
array_push($comments, new Comment($result["title"], $result["content"], $result["author"]));

Answer 1

fetch() returns a single record. When you foreach() over the result, you iterator the values of the row, not rows.
Use fetchAll() to get all records.
$results = $stmt->fetchAll();
foreach ($results as $result) {
echo $result['title'];
}
In your initial code :
$results = $stmt->fetch();
foreach ($results as $result) {
echo $result; // here $result is id, then title, and so on.
}