get additional data on same collection in Mongodb C#

Question

I have a collection called "User". I'm passing userid to get the record. In addition to that i also need additional 10 last updatedAt(DateTime) record excluding the userid record but added together. So, total returned result will be 11 in this case. Is that possible using same query? I tried using Or and lookup but can't make it work as expected. Any help is appreciated.

 User collection:
[{
     "id" : "123456", 
    "name" : "foo", 
    "addressIds" : [ObjectId(234567)]
  }     ,
    "id" : "345678", 
    "name" : "bar", 
    "addressIds" : [ObjectId(678565), ObjectId(567456)]
   }]

 Address collection:
 [{
 "_id":"234567",
 "district" : "district1", 
 "pincode" : "568923",
  },
  {
 "_id":"678565",
 "district" : "district2", 
 "pincode" : "568924",
  },
  {
 "_id":"567456",
 "district" : "district3", 
 "pincode" : "568925",
 }]

Using facets, i have the User and the addressIds. Can i have the actual documents for AddressIds in User?

You can use $facet: mongodb.com/docs/manual/reference/operator/aggregation/facet — nimrod serok
– nimrod serok, Commented Apr 7, 2022 at 15:34

nimrod serok · Accepted Answer · 2022-04-07 18:15:43Z

1

Edit: You can use $facet, like this:

db.collection.aggregate([
  {$sort: {date: -1}},
  {$facet: {
      byTate: [{$limit: 10}],
      byUser: [{$match: {userId: 455845}}]
    }
  },
  {$project: {
    byDate: {
        $filter: {
            input: "$byDate",
            as: "item",
            cond: {$ne: ["$$item",{"$arrayElemAt": ["$byUser", 0]}]}
        }
    },
    byUser: 1,
    }
  },
  {
    $project: {
      byDate: {$slice: ["$byDate", 10]},
      byUser: 1
    }
  }
])

You can see it works on the playground .

Switch between userId: 455845 / 455845 to see both cases.

edited Apr 7, 2022 at 18:15

answered Apr 7, 2022 at 15:38

nimrod serok

16.1k2 gold badges15 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

CKK Over a year ago

Thanks for the response. This is what i'm looking for. Only question is how do i get the distinct record? Meaning, userId may be inside the bydate result but i want the distinct byDate to not have userId in it.

nimrod serok Over a year ago

Answer is edited

CKK Over a year ago

I have the required document through facets. I need to get the details from another collection using the reference Ids that i have from facets. Is it possible to use lookup inside facets on single query?

nimrod serok Over a year ago

According to the docs no problem.

CKK Over a year ago

I have added the sample. I'm able to do this using compass. I used lookup first to get the address inside the User and then use facets to filter the Ids and get 10 more record as you have shown. But i'm not able to do this in C#.

Collectives™ on Stack Overflow

get additional data on same collection in Mongodb C#

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related