CODEWITHSUNDEEP
mongodbmongodb-queryaggregation-framework
Guilherme Reda
Guilherme Reda

Reputation: 115

Check if value don't exists in sub document of sub document

I the following schema.

var UserSchema = new Schema({
    messages: [{
        username: String,
        read: [{
            type: { type: String, enum: ['A','B','C'] },
        }]
    }],
});

var MySchema = new Schema({
    users: [UserSchema]
});

I need to count how many occurrences in MySchema that the last message of each user don't have the read value as 'A'

I need to use aggregate, so that I can join with an existing query.

Upvotes: 1

Views: 467

Answers (1)

kkkkkkk
kkkkkkk

Reputation: 7748

This should work, if it does not please include some sample data and expected result so that I will update my answer later:

db.collection.aggregate([
  {
    $unwind: '$users',
  },
  {
    $project: {
      lastMessage: {
        $arrayElemAt: ['$users.messages', -1],
      },
    },
  },
  {
    $unwind: '$lastMessage.read',
  },
  {
    $group: {
      _id: '$_id',
      read: {
        $push: '$lastMessage.read',
      },
    },
  },
  {
    $match: {
      read: {
        $nin: ['A']
      }
    }
  },
  {
    $count: 'count'
  }
])

Upvotes: 1

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