How to add new key-value to existing array in PHP - php

Question

I have a form in PHP that takes in two values: server_id and user_id (which can be more than one separated by ','). I retrieve some data from a table and stored them as array. Using the same server_id and user_id, I would like to retrieve additional from another table but store them into the same array.
This is what I have so far.
//Data from PHP form stored in array
$inputData = Array ( [server_id] => 10
[user_id] => Array ( [0] => 111[1] => 222) )
//Existing array storing data retrieved from persons table
$userData =
Array
(
[0] => Array
(
[user_id] => 111
[server_id] => 10
[user_name] => Harry Pottter
[user_age] => 18 )
[1] => Array
(
[user_id] => 222
[server_id] => 10
[user_name] => Hermione
[user_age] => 18 )
)
//retrieving additional data from user_contact table
$sql = "SELECT user_phone, user_address FROM user_contact
WHERE user_id = ? AND server_id = ?";
foreach($user_id as $user)
{
$statement= $DB->link->prepare($sql);
$statement->bind_param("si", $server_id, $user);
$statement->execute();
if($resultSet = $statement->get_result())
{
while($row = $resultSet->fetch_assoc())
{
userData[$key]['user_phone'] = $row['user_phone'];
userData[$key]['user_address'] = $row['user_address'];
}
}
}

Answer 1

try using array_push()
like
<?php
$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>