Question

我是MongoDB的新手，目前正在使用Atlas托管的MongoDB。

我的代码使用PHP MongoDB库。

数据库有一个名为“ transactions”的集合，其结构如下：

[  
   {  
      "product":"X",
      "customer":"John",
      "history":[  
         {  
            "payment_date":"2017-07-01",
            "status":"paid"
         },
         {  
            "payment_date":"2017-08-02",
            "status":"paid"
         },
         {  
            "payment_date":"2017-09-03",
            "status":"paid"
         }
      ]
   },
   {  
      "product":"Y",
      "customer":"Mary",
      "history":[  
         {  
            "payment_date":"2017-07-01",
            "status":"paid"
         },
         {  
            "payment_date":"2017-08-02",
            "status":"paid"
         },
         {  
            "payment_date":"2017-09-03",
            "status":"paid"
         }
      ]
   }
]

基于此答案https://stackoverflow.com/a/39549711/1229477，我有以下代码尝试查找付款日期等于2017-08-02的历史记录

$manager = new \MongoDB\Driver\Manager(getenv('MONGODB_DSN'));
$db = new \MongoDB\Database($manager, getenv('MONGODB_DATABASE'));
$cursor = $db->transaction->find(
    ['history.payment_date' => '2017-08-02'],
    ['_id' => 0, 'history' => ['$elemMatch' => ['history.payment_date' => '2017-08-02']]]
);
return $cursor->toArray();

但是它不返回任何项目！

我尝试在MongoShell中运行代码！

我还尝试了一些使用聚合的代码：

$manager = new \MongoDB\Driver\Manager(getenv('MONGODB_DSN'));
$db = new \MongoDB\Database($manager, getenv('MONGODB_DATABASE'));
$cursor = $db->transaction->aggregate(
    [
        [
            '$match' => [
                'history.payment_date' => "2017-08-02"
            ]
        ],
        [
            '$project' => [
                '_id' => 0,
                'history' => 1
            ]
        ]
    ]
);
return $cursor->toArray();

我跟踪了很多链接，但其中任何一个都没有成功！因此，如果您不给我其他链接，我们将不胜感激，因为我已经访问了数百个！

Answer 1

我会尝试一下：

$cursor = $db->transaction->aggregate(
    [
        [
            '$match' => [
                'history.payment_date' => "2017-08-02" // limit returned documents to ones with matches
            ]
        ],
        [
            '$unwind' => "$history" // split each document into multiple documents based on history
        ],
        [
            '$match' => [
                'history.payment_date' => "2017-08-02" // only return documents that match
            ]
        ]
    ]
);

如何使用MongoDB PHP库仅返回匹配的数组项

1 个答案: