counting

For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

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Count MongoDB Search Results

The MongoDB Search count option adds a field to the [metadata results](https://www.mongodb.com/docs/search/query/aggregation-stages/searchmeta.md#std-label-fts-metadata-results document that displays a count of the search results for the query. You can use count to determine the size of the result set. You can use it in the [$search](https://www.mongodb.com/docs/search/query/aggregation-stages/search.md#mongodb-pipeline-pipe.-search or [$searchMeta](https://www.mongodb.com/docs/search/query/aggregation-stages/searchmeta.md#mongodb-pipeline-pipe.-searchMeta stage. You must use it in conjunction with the [operators](https://www.mongodb.com/docs/search/query/operators-collectors/overview.md#std-label-operators-ref or [collectors](https://www.mongodb.com/docs/search/query/operators-collectors/overview.md#std-label-collectors-ref to display either the total number of documents or a lower bound on the number of documents that match the query.

MongoDB recommends using count with the [$searchMeta](https://www.mongodb.com/docs/search/query/aggregation-stages/searchmeta.md#mongodb-pipeline-pipe.-searchMeta stage to retrieve metadata results only for the query. To retrieve metadata results and query results using the [$search](https://www.mongodb.com/docs/search/query/aggregation-stages/search.md#mongodb-pipeline-pipe.-search stage, you must use the $$SEARCH_META variable. To learn more, see [SEARCH_META Aggregation Variable.](https://www.mongodb.com/docs/search/query/counting.md#std-label-fts-count-aggregation-variable

Considerations

To use the count option over sharded collections, your cluster must run MongoDB 7.0 or later. On sharded clusters running MongoDB 7.2.0, [$searchMeta](https://www.mongodb.com/docs/search/query/aggregation-stages/searchmeta.md#mongodb-pipeline-pipe.-searchMeta might return an error for count.

MongoDB Search doesn't include the count results in the results for queries run with count in [explain](https://www.mongodb.com/docs/search/query/explain.md#std-label-explain-ref mode.

Syntax

count has the following syntax:

{
  "$searchMeta"|"$search": {
    "index": "<index name>", // optional, defaults to "default"
    "<operator>": {
      <operator-specifications>
    },
    "count": {
      "type": "lowerBound"|"total",
      "threshold": <number-of-documents> //optional
    }
  }
}

Options

Count Results

The count document included in the results document contains the following integer fields:

SEARCH_META Aggregation Variable

When you run your query using the [$search](https://www.mongodb.com/docs/search/query/aggregation-stages/search.md#mongodb-pipeline-pipe.-search stage, MongoDB Search stores the metadata results in the $$SEARCH_META variable and returns only the search results. You can use the $$SEARCH_META variable in all the supported aggregation pipeline stages to view the metadata results for your [$search](https://www.mongodb.com/docs/search/query/aggregation-stages/search.md#mongodb-pipeline-pipe.-search query. You can also use the $$SEARCH_META variable with [facet.aggregations.](https://www.mongodb.com/docs/search/query/operators-collectors/facet.md#std-label-fts-facet-aggregation

MongoDB recommends using the $$SEARCH_META variable only if you need both the search results and the metadata results. Otherwise, use the:

• [$search](https://www.mongodb.com/docs/search/query/aggregation-stages/search.md#mongodb-pipeline-pipe.-search stage for just the search results.

• [$searchMeta](https://www.mongodb.com/docs/search/query/aggregation-stages/searchmeta.md#mongodb-pipeline-pipe.-searchMeta stage for just the metadata results.

Example:

Basic

Suppose an index on the released field in the sample_mflix.movies collection:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "released": {
        "type": "date"
      }
    }
  }
}

The following query searches for movies released near September 01, 2011 in the movies collection. The query requests a total count of the results. The query includes a:

The sample query uses the following stages:

db.movies.aggregate([
  {
    "$search": {
      "near": {
        "path": "released",
        "origin": ISODate("2011-09-01T00:00:00.000+00:00"),
        "pivot": 7776000000
      },
      "count": {
         "type": "total"
      }
    }
  },
  {
    "$project": {
      "meta": "$$SEARCH_META",
      "title": 1,
      "released": 1
    }
  },
  {
    "$limit": 2
  }
])

Output:

{
  "_id" : ObjectId("573a13c3f29313caabd6b025"),
  "title" : "Submarino",
  "released" : ISODate("2011-09-01T00:00:00Z"),
  "meta" : {
    "count" : { "total" : NumberLong(23026) }
  }
}
{
  "_id" : ObjectId("573a13c7f29313caabd748f7"),
  "title" : "Devil's Playground",
  "released" : ISODate("2011-09-01T00:00:00Z"),
  "meta" : {
    "count" : { "total" : NumberLong(23026) }
  }
}

To learn more about the results, see [Count Results.](https://www.mongodb.com/docs/search/query/counting.md#std-label-count-results

Examples

The following example uses an index on the year field in the sample_mflix.movies collection:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "year": {
        "type": "number"
      }
    }
  }
}

lowerBound Example

The following query searches for the movies between the years 2010 and 2015 in the movies collection. The query requests a lower bound count of the results:

db.movies.aggregate([
  {
    "$searchMeta": {
      "range": {
        "path": "year",
        "gte": 2010,
        "lte": 2015
      },
      "count": {
        "type": "lowerBound"
      }
    }
  }
])

MongoDB Search returns the following results:

{ "count" : { "lowerBound" : NumberLong(1001) } }