如何在PHP中输出自定义JSON

我正在尝试在从MySQL提取数据之前添加其他信息，以便我可以json格式输出它，但是，我不确定如何在php中获取所需的结构。

我似乎无法用实际的数据字符串（即RoomID = 1）而不是（值0 = 1）替换json值（0,1,3,4），然后数组结构是完全的，并且不能修正它。这是我到目前为止尝试过的。

<?php

$floorID = $_GET['FloorID'];

$roomID = '';
$roomName = '';
$description ='';
$image = '';

if ($floorID != '')
{

    $conn = mysql_connect($servername, $db_username, $db_password, $dbname);
    mysql_select_db($dbname);


    $query = "SELECT * FROM `Apartments` WHERE FloorID = '$floorID'";
    if (!$result = mysql_query($query))
    {
        die("Error: " . mysql_error($con));
    }


      $data = array(
      'message' => 'Your message here',
      'value'   => array()
      );


  while($r = mysql_fetch_assoc($result)) {
     $data['value'][] = array(
        $roomID  = $r['RoomID'],
        $roomName = $r['RoomName'],
        $description = $r['Description'],
        $image = $r['Image'],

     );
}

  echo json_encode($data);
  mysql_close($conn);

    }


?>

这是我得到的json ..

{
  "message": "Your message here",
  "value": [
    [
      "1",
      "Coffee",
      "This is the great coffee session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "4 hours"
    ],
    [
      "1",
      "Tea",
      "This is the great tea session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hours"
    ],
    [
      "1",
      "Herb",
      "This is the great Herb session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "1 hour"
    ],
    [
      "2",
      "mechanic",
      "This is the great mechanic session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ],
    [
      "2",
      "navigator",
      "This is the great navigator session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ],
    [
      "2",
      "detective",
      "This is the great detective session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ],
    [
      "3",
      "housekeeper",
      "This is the great housekeeper session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ],
    [
      "3",
      "piano",
      "This is the great piano session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ],
    [
      "3",
      "piano",
      "This is the great piano session",
      "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/1200px-A_small_cup_of_coffee.JPG",
      "Public",
      "2 hour"
    ]
  ]
}

但这是我想要获得的Json结构。

[
    {
        "FloorID" : 1,
        "ApartmentID" : 1,
        "AllRooms" : [
            {
                "RoomID" : 1,
                "RoomName" : "room One",
                "duration" : "",
                "image" : "https://image.flaticon.com/icons/png/512/1458/1458512.png"
            },
            {
                "RoomID" : 2,
                "RoomName" : "room Two",
                "duration" : "",
                "image" : "https://i.pinimg.com/originals/62/1a/b7/621ab74618686de0f2a3bed8b4080e90.png"
            },
            {
                "RoomID" : 3,
                "RoomName" : "room Three",
                "duration" : "",
                "image" : "https://visiblehr.com/wp-content/uploads/2019/09/6.png"
            },
            {
                "RoomID" : 4,
                "RoomName" : "room Four",
                "duration" : "",
                "image" : "https://image.flaticon.com/icons/png/512/1458/1458512.png"
            }
        ]

    },
    {
        "FloorID" : 1,
        "ApartmentID" : 2,
        "AllRooms" : [
            {
                "RoomID" : 5,
                "RoomName" : "room two one",
                "duration" : "",
                "image" : "https://image.flaticon.com/icons/png/512/1458/1458512.png"
            },
            {
                "RoomID" : 6,
                "RoomName" : "Session two Two",
                "duration" : "",
                "image" : "https://image.flaticon.com/icons/png/512/1458/1458512.png"
            }
        ]

    }
]

如您所见，我的输出未显示值的名称，而是保留为空？有人可以引导我进入正确的道路吗？我是json和php的新手，谢谢。