将数组推入数组然后编码 - PHP

I'm trying to combine a few mySQL queries in a single PHP and push it all into a single JSON object.

So, I'm starting with the first query...like this:

$data=[];

$response = $stmt->fetchAll(PDO::FETCH_ASSOC);
$final_count = count($response);
$data['count'] = $final_count;

If I then do echo json_encode($data); I get a nicely formatted object like: {"count":61}

I then have a second query that I put the results through a loop, like so:

$response = $stmt->fetchAll(PDO::FETCH_ASSOC);
$items = array();
foreach ($response as &$value) {
    $items[] = $value['date_added'];
}
echo json_encode($items);

And I get my nice set of dates:

["2017-06-24 00:08:58","2017-06-26 15:01:48","2017-06-27 15:01:48","2017-06-28 23:19:41","2017-06-29 01:38:07","2017-06-30 00:08:58"]

Here's the question, how do I get this all back together like so:

{
    "count": 61,
    "dates": [
        "2017-06-24 00:08:58",
        "2017-06-26 15:01:48",
        "2017-06-27 15:01:48",
        "2017-06-28 23:19:41",
        "2017-06-29 01:38:07",
        "2017-06-30 00:08:58"
    ]
}

You could use

 $myData['count'] = $final_count;
 $myData['dates'] = $items
 echo json_encode($myData);

$data=[];

$response = $stmt->fetchAll(PDO::FETCH_ASSOC);
$final_count = count($response);
// first store count in `$data`
$data['count'] = $final_count;

$data['dates'] = [];
$response = $stmt->fetchAll(PDO::FETCH_ASSOC);
// next, store dates in subarray of `$data`
foreach ($response as &$value) {
    $data['dates'][] = $value['date_added'];
}

// finally encode everything
echo json_encode($data);

Of course you can use array_merge of all your collected data.

Or:

$data=[];
// get $final_count
$data['count'] = $final_count;
// ... do some more stuff
// load items from db
$data['dates'] = $items;

echo json_encode($data);