Let us create a collection with documents −
> db.demo568.insertOne({ _id: 101, details: [ {id : 101 }, { id:103 } ] }); { "acknowledged" : true, "insertedId" : 101 }
Display all documents from a collection with the help of find() method −
> db.demo568.find();
This will produce the following output −
{ "_id" : 101, "details" : [ { "id" : 101 }, { "id" : 103 } ] } Following is the query to create second collection: > db.demo569.insertOne({ _id: 101, details: "John" }) { "acknowledged" : true, "insertedId" : 101 } > db.demo569.insertOne({ _id: 102, details: "Chris" }) { "acknowledged" : true, "insertedId" : 102 } > db.demo569.insertOne({ _id: 103, details: "David" }) { "acknowledged" : true, "insertedId" : 103 }
Display all documents from a collection with the help of find() method −
> db.demo569.find();
This will produce the following output −
{ "_id" : 101, "details" : "John" } { "_id" : 102, "details" : "Chris" } { "_id" : 103, "details" : "David" }
Following is the query to match documents whose _id is in an array as part of a subdocument −
> db.demo569.find({ '_id': { '$in': db.demo568.distinct('details.id', {'_id': 101}) }})
This will produce the following output −
{ "_id" : 101, "details" : "John" } { "_id" : 103, "details" : "David" }