Question

我有这两个集合，我需要使用第一个集合的参数从其中一个集合进行查询

收藏范例：

Collection 1 :{
id: 1234,
lastDate : "2020-09-10T08:30:14.960+00:00"
}

Collection 2 :{
site : 1234,
date : "2020-09-10T08:30:14.960+00:00"
}

我需要从集合1获取ID和“ lastDate”，并使用它在集合2上进行查询

对不起，不好的解释告诉您是否需要更多信息或其他信息

等效的SQL

SELECT * FROM collection2 
WHERE site IN (SELECT id FROM collection1) and
 date IN (SELECT lastDate FROM collection1);

Answer 1

 let params  = {_id:1}
 let data = await Collection1.aggregate([
    {$match:params},
   {
      $lookup: {
        from: "collection2",
        localField: "$collection1datefield",
        foreignField: "$collection2datefield",
        as: "collection2Object"
      }
   }
  ])

Answer 2

如果您已完成对第一个集合的引用，则可以使用简单查询，即

const query = await Collection1.findOne({id: req.params.id}).populate('site lastDate');

Answer 3

 db.FIRST_COLLECTION.aggregate([
  {
    $lookup: {
      from: "FIRST_COLLECTION",
      localField: "id", // local field of first collection
      foreignField: "site", // foreign field at second collection
      as: "liste",
    },
  },
  { $unwind: "$liste" },
  {
    $group: {
      _id: "$site",
      data: {
        $addToSet: {
          site: $site,
          date: $date,
        },
      },
    },
  },
]);

我邀请您阅读有关Aggregation

的更多信息

使用mongoose和NodeJS在Mongo DB中嵌套查询

3 个答案: