将SQL数组数据解析为php mail（）

Question

I'm doing an SQL SELECT to retrieve client data to then generate an email from. The $param that is being parsed to the API is an object:

var param = {
  delivery_id: "string",
  order_id: "string",
}

The order_id is then being used to query a second table:

$param = $_REQUEST['param'];
$param = json_decode($param);
$collname = "orders";
$sql = 'SELECT * FROM '.$collname.' WHERE `id` = '.$param->order_id;

$result = $conn->query($sql); 
//$conn is defined externally, and is not the cause of the problem

$aData = array();

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $aData[] = $row;
    }
    sendEmail($aData);
} else {
    echo "Error";
}

mysqli_close($conn);

This first query makes perfect sense, and when the $aData is being returned to the front end as a string, it looks like expected; an array of objects (one object).

But when I try to access it in the sendEmail function, it can't access the key values. Same when I try to echo json_encode($aData[0]->id) (doesn't work) instead of just echoing json_encode($aData[0]) (works).

The email is actually sent to the hard-coded BCC-mail, but without any of the values within the array.

function sendEmail(&$aData){

    $to = $aData[0]->contact_email;
    $subject = "".$aData[0]->id;
    $txt = "Something something ".$aData[0]->contact.",
    something something.
    ";
    $headers = "From: [e-mail]" . "
" .
    "BCC: [e-mail]";

    mail($to,$subject,$txt,$headers);
}

How do I access the object keys in the API?

EDIT: question answered by S.DEV. Since data was returned as associative array and not an object, correct targeting syntax was $aData[0]['id'].

Answer 1

You can try as following:

while($row = $result->fetch_assoc()) {
        //$aData[] = $row;
        sendEmail($row);
}
//function sendEmail(&$aData){ 
function sendEmail($aData){