我有以下查询：
ManifestImage::whereBetween('created_at', [$img->created_at, $fewseconds])->whereNull('original_pdf')->get();
这很好地获得了我需要的正确记录，但是我想更进一步。现在，这是一个示例返回：
[{"id":404,"manifest_id":3601,"name":"3601_1559451552023428000.jpeg","mime":"image\/jpeg","type":"jpeg","created_at":"2019-06-01 22:59:12","updated_at":"2019-11-11 14:47:08","original_pdf":null,"image_type":2,"temp_group":null},
{"id":405,"manifest_id":3601,"name":"3601_1559451552068266200.jpeg","mime":"image\/jpeg","type":"jpeg","created_at":"2019-06-01 22:59:12","updated_at":"2019-11-11 14:47:08","original_pdf":null,"image_type":2,"temp_group":null},{"id":406,"manifest_id":3601,"name":"3601_1559451553041321000.jpeg","mime":"image\/jpeg","type":"jpeg","created_at":"2019-06-01 22:59:13","updated_at":"2019-11-11 14:47:08","original_pdf":null,"image_type":2,"temp_group":null}]
我想检查的是，以上返回的所有记录是否只有manifest_id的一个值。所有这些都具有3601的值，所以我想做的是通过一个条件语句，如果该条件集中只有一个唯一的数字，则继续下一步，否则将其完全跳过。