MongoDB使用一个集合中的一系列ID来根据另一个集合的ID进行过滤结果

发布于 2025-02-13 12:16:22 字数 700 浏览 0 评论 0原文

假设有一个MongoDB集合Colla。说colla具有以下三个文档：

{"_id": "1", "name": "Bob"},
{"_id": "2", "name": "John"},
{"_id": "3", "name": "Will"}

假设还有另一个MongoDB Collection CollB具有以下文档：

{
    "_id": "1", 
    "foo": {
        "arr": ["1", "3"]
    }
}

MongoDB中是否有办法查询collb foo.arr数组内容（[“ 1”]，[“ 3”]），并使用它来检索文档Colla具有这些_id值，以产生以下结果：

{"_id": "1", "name": "Bob"},
{"_id": "3", "name": "Will"}

原文

Suppose there is a MongoDB Collection CollA. Say CollA has the following three Documents:

{"_id": "1", "name": "Bob"},
{"_id": "2", "name": "John"},
{"_id": "3", "name": "Will"}

Let's say there is another MongoDB Collection CollB which has the following Document:

{
    "_id": "1", 
    "foo": {
        "arr": ["1", "3"]
    }
}

Is there a way in MongoDB to query CollB for the foo.arr array contents (["1"],["3"]) and use it to retrieve the Documents in CollA which have these _id values, to produce the following result:

{"_id": "1", "name": "Bob"},
{"_id": "3", "name": "Will"}

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恋你朝朝暮暮 2025-02-20 12:16:24

从collb执行简单$查找。在$ lookup结果 $ undind 之后，使用$替换 $ lookup

db.CollB.aggregate([
  {
    "$lookup": {
      "from": "CollA",
      "localField": "foo.arr",
      "foreignField": "_id",
      "as": "collALookup"
    }
  },
  {
    "$unwind": "$collALookup"
  },
  {
    "$replaceRoot": {
      "newRoot": "$collALookup"
    }
  }
])

结果是 mongo playground 供您参考。

Perform a simple $lookup from CollB. Use $replaceRoot with the $lookup result after $unwind

db.CollB.aggregate([
  {
    "$lookup": {
      "from": "CollA",
      "localField": "foo.arr",
      "foreignField": "_id",
      "as": "collALookup"
    }
  },
  {
    "$unwind": "$collALookup"
  },
  {
    "$replaceRoot": {
      "newRoot": "$collALookup"
    }
  }
])

Here is the Mongo Playground for your reference.

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踏雪无痕 2025-02-20 12:16:24

查询

查找_id带有数组foo.arr和限制1的字段，我们只是在意是否加入
无需将许多文档保存
到
（

存储如果您只需要1个collb的特定文档，我认为从collb开始像雷的答案一样有意义，但是在$ match $ yougp $ lookup 之前，请添加$ match。 collb）

playmongo

collA.aggregate(
[{"$lookup": 
   {"from": "collB",
    "localField": "_id",
    "foreignField": "foo.arr",
    "pipeline": [{"$limit": 1}],
    "as": "results"}},
 {"$match": {"$expr": {"$ne": ["$results", []]}}},
 {"$unset": ["results"]}])

Query

lookup _id field with array foo.arr and limit 1, we just care if joined
(no need to save many documents to memory)
keep documents that joined (not empty results)
unset the results field

*this will keep from collA all the documents that their _id, are in any array in collB (if you want only for 1 specific document of collB i think starting from collB like ray's answer makes more sense, but add a $match also before the $lookup for the 1 member of collB)

Playmongo

collA.aggregate(
[{"$lookup": 
   {"from": "collB",
    "localField": "_id",
    "foreignField": "foo.arr",
    "pipeline": [{"$limit": 1}],
    "as": "results"}},
 {"$match": {"$expr": {"$ne": ["$results", []]}}},
 {"$unset": ["results"]}])

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