mysql to pdo JSON for ios - php

Question

I'm trying to convert this mysql code into PDO code, yet I can only return one of my rows in JSON whereas the mysql code allows me all the rows.
$connection = mysql_connect($host, $user, $pass);
//Check to see if we can connect to the server
if(!$connection)
{
die("Database server connection failed.");
}
else
{
//Attempt to select the database
$dbconnect = mysql_select_db($db, $connection);
//Check to see if we could select the database
if(!$dbconnect)
{
die("Unable to connect to the specified database!");
}
else
{
$query = "SELECT * FROM questions ORDER BY RAND() LIMIT 40";
$resultset = mysql_query($query, $connection);
$records = array();
//Loop through all our records and add them to our array
while($r = mysql_fetch_assoc($resultset))
{
$records[] = $r;
}
//Output the data as JSON
echo json_encode($records);
}
}
And here is the PDO code I've got to so far
$db = new PDO('mysql:host=***;dbname=***', $user, $pass);
$query = "SELECT * FROM questions ORDER BY RAND() LIMIT 40";
$stmt = $db->prepare($query);
$stmt->execute();
$records = array();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$records = $row;
}
echo json_encode($records);
It looks like I have to fill some more of this post out with random gobldygook as it seems I haven't already gotten to the point.

Answer 1

forgot to push each row into records, therefore
$records[] = $row;
or use fetchAll()
$db = new PDO('mysql:host=***;dbname=***', $user, $pass);
$query = "SELECT * FROM questions ORDER BY RAND() LIMIT 40";
$stmt = $db->prepare($query);
$stmt->execute();
$records = $stmt->fetchAll(PDO::FETCH_ASSOC); // to get all records at once
echo json_encode($records);