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I am trying to generate a new collection with a field 'desc' having into account a condition in field in a documment array. To do so, I am using $cond statement

The origin collection example is the next one:

"_id" : ObjectId("5e8ef9a23e4f255bb41b9b40"), "Brand" : { "models" : [ "name" : "AA" "name" : "BB" "_id" : ObjectId("5e8ef9a83e4f255bb41b9b41"), "Brand" : { "models" : [ "name" : "AG" "name" : "AA"

The query is the next:

db.runCommand({
    aggregate: 'cars',
    'pipeline': [
            '$project': {
                'desc': {
                    '$cond': {
                        if: {
                            $in: ['$Brand.models.name',['BB','TC','TS']]
                        then: 'Good',
                        else: 'Bad'
            '$project': {
                'desc': 1
            $out: 'cars_stg'
    'allowDiskUse': true,
The problem is that the $cond statement is always returning the "else" value. I also have tried $or statement with $eq or the $and with $ne, but is always returning "else".
What am I doing wrong, or how should I fix this?
Thanks
Since $Brand.models.name returns an array, we cannot use $in operator.
Instead, we can use $setIntersection which returns an array that contains the elements that appear in every input array
db.cars.aggregate([
    "$project": {
      "desc": {
        "$cond": [
            $gt: [
                $size: {
                  $setIntersection: [
                    "$Brand.models.name",
                      "BB",
                      "TC",
          "Good",
          "Bad"
    "$project": {
      "desc": 1
      $out: 'cars_stg'
MongoPlayground | Alternative $reduce
        
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