查询MongoDB文档中的子图表，并且仅返回匹配的子图表

发布于 2025-02-10 21:13:33 字数 1181 浏览 1 评论 0原文

我在这里看： https://codelikethis.com/查询在这里： https://www.mongodb.com/community/forums/t/what-what------在mongodb/115315中使用sub-documents 尝试弄清楚如何仅查询父母文档中的子图表。

这是数据的示例：

{'testname':'process',
'jobId':"job1",
"vt_cond":"cond1",
"testData":[{
'chip':'c1',
'name':'block1'},
{
'chip':'c1',
'name':'block1'},
{
'chip':'c1',
'name':'block2'},
{
'chip':'c1',
'name':'block3'}]}

它包含“ TestData”字段中的子图表。我想做的是以下内容：

db.collection.find({'jobId':'job1', 'testData.name':'block3'})

让它返回以下内容：

{'testname':'process',
'jobId':"job1",
"vt_cond":"cond1",
"testData":[{'chip':'c1',
'name':'block3'}]}

i 了解 MongoDB文档指出它将查询并返回与子记录查询条件中条件相匹配的文档。确实如此。我得到了上面的整个示例文档。 无论如何，我是否可以使用与上述类似的条件进行类似的查询，并且只能返回带有所需子记录的父节点，而不是所有子图表？

原文

Ive looked here: https://codelikethis.com/lessons/db/mongodb-array-queries and here: https://www.mongodb.com/community/forums/t/what-is-the-best-way-to-query-an-array-of-sub-documents-in-mongodb/115315 to try and figure out how to query only matching subdocuments from a parent document.

Here is an example of the data:

{'testname':'process',
'jobId':"job1",
"vt_cond":"cond1",
"testData":[{
'chip':'c1',
'name':'block1'},
{
'chip':'c1',
'name':'block1'},
{
'chip':'c1',
'name':'block2'},
{
'chip':'c1',
'name':'block3'}]}

It contains subdocuments within the "testData" field. What I want to do is something like the following:

db.collection.find({'jobId':'job1', 'testData.name':'block3'})

and have it return the following:

{'testname':'process',
'jobId':"job1",
"vt_cond":"cond1",
"testData":[{'chip':'c1',
'name':'block3'}]}

I understand that the mongodb documentation states it will query and return a document which matches the conditions in the subdocument query conditions. It does. I get the entire example document as above. Is there anyway where I can make a similar query with similar conditions as above, and only return the parent node with the desired subdocument, instead of ALL the subdocuments?

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绝影如岚 2025-02-17 21:13:33

选项1：您可以在项目部分中使用$ Elemmatch如下：

db.collection.find({
  "jobId": "job1",
  "testData.name": "block3"
},
{
 "testData": {
   "$elemMatch": {
      name: "block3"
  }
}
})

说明：

仅找到匹配标准的数组sub-object符合标准的

关注：仅当您仅需要1倍时才能工作匹配数组的匹配元素，如果匹配条件中的一个元素要多于一个元素，则可以更好地使用选项2

。 a>

选项2：汇总/$ filter（当您在阵列中匹配的阵列中一个对象时，请覆盖以下情况）

  db.collection.aggregate([
 {
  $match: {
  "jobId": "job1",
  "testData.name": "block3"
  }
 },
 {
  "$addFields": {
   "testData": {
    "$filter": {
      "input": "$testData",
      "as": "t",
      "cond": {
        $eq: [
          "$t.name",
          "block3"
          ]
        }
      }
    }
   }
 }
])

解释：

匹配文档
过滤器仅在对象数组中匹配的对象

态

Option 1: You can use $elemMatch in the project part as follow:

db.collection.find({
  "jobId": "job1",
  "testData.name": "block3"
},
{
 "testData": {
   "$elemMatch": {
      name: "block3"
  }
}
})

Explained:

Find the object and project only the array sub-object that match the criteria

Attention: This is only working if you need only 1x matching element from array , if there is more then one element in the array matching the criteria better use Option 2.

Playground

Option 2: aggregate/$filter ( cover the case when you have more then one objects in the array matching by the filter )

  db.collection.aggregate([
 {
  $match: {
  "jobId": "job1",
  "testData.name": "block3"
  }
 },
 {
  "$addFields": {
   "testData": {
    "$filter": {
      "input": "$testData",
      "as": "t",
      "cond": {
        $eq: [
          "$t.name",
          "block3"
          ]
        }
      }
    }
   }
 }
])

Explained: