MongoDB filter multiple sub-documents?

To filter multiple sub-documents in MongoDB, use aggregate(). Let us create a collection with documents −

> db.demo200.insertOne(
...   {
...      "Id":"101",
...      "details1":[
...         {
...            "isActive":true,
...            "SubjectName":"MySQL"
...         },{
...            "isActive":false,
...            "SubjectName":"Java"

...         }
...      ],
...      "details2":[
...         {
...            "isActive":false,
...            "Name":"David"
...         },{
...            "isActive":true,
...            "Name":"Mike"
...         }
...      ]
...   }
...);
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e3c374f03d395bdc21346e4")
}

Display all documents from a collection with the help of find() method −

> db.demo200.find();

This will produce the following output −

{
   "_id" : ObjectId("5e3c374f03d395bdc21346e4"), "Id" : "101", "details1" : [
      { "isActive" : true, "SubjectName" : "MySQL" },
      { "isActive" : false, "SubjectName" : "Java" } ], "details2" : [ { "isActive" : false, "Name" : "David" },
      { "isActive" : true, "Name" : "Mike" }
   ]
}

Following is the query to filter multiple sub-documents −

> var out= [
...   {
...      "$match": {
...         "Id": "101",
...         "details1.isActive": true,
...         "details2.isActive": true
...      }
...   },
...   { "$unwind": "$details1" },
...   { "$unwind": "$details2" },
...   {
...      "$match": {
...         "details1.isActive": true,
...         "details2.isActive": true
...      }
...   },
...   {
...      "$group": {
...         "_id": {
...            "_id": "$_id",
...            "Id": "$Id"
...         },
...         "details2": { "$addToSet" : "$details2" },
...         "details1": { "$addToSet" : "$details1" }
...      }
...   },
...   {
...      "$project": {
...         "_id": 0,
...         "Id": "$_id.Id",
...         "details2": 1,
...         "details1": 1
...      }
...   }
...]
>
> db.demo200.aggregate(out)

This will produce the following output −

{ "details2" : [ { "isActive" : true, "Name" : "Mike" } ], "details1" : [ { "isActive" : true, "SubjectName" : "MySQL" } ], "Id" : "101" }