从MySQL获取数组

Question

I am querying MySQL to perform an operation and return an array. To do this I am using the following code:

$return_array = array(
        "title" => "nearby media",
        "nearby_media_list" => array()
    );

$my_query = "select * from `Media`";
$result = $conn->query($my_query);

while($row = $result->fetch_assoc()) {
    $mediaLat = $row["lat"];
    $mediaLon = $row["lon"];

    $calculated_distance = distance( $userLat, $userLon, $mediaLat, $mediaLon, "M");

    if( $calculated_distance <= $distance_limit ) {
        // Build array
        $return_array["nearby_media_list"][] = array(
                                               'uid' => $row['uid']   
                                            );
    }
}

echo json_encode($return_array);

$conn->close();
?>

and my output looks like this:

{"title":"nearby media","nearby_media_list":[{"uid":"-Kn1f0jo_36qnQBCqjCq"}]}

Since the array only contains one type of data I don't need to store a key and don't need JSON. What I want is a simple array of the values separated by a token so I can take it apart more easily. desired outcome is something like

[value1@#$%value2@#$%]

Can anyone instruct me how to do this? I haven't had any luck