# Limit search result based on a field **URL:** \ **Category:** Elasticsearch\ **Created:** [October 29, 2018, 5:06pm UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476 "2018-10-29T17:06:19Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![cweinberger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cweinberger/32/33147_2.png) [@cweinberger](https://discuss.elastic.co/u/cweinberger)\ **Post date:** [October 29, 2018, 5:06pm UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/1 "2018-10-29T17:06:19Z")
Hi there, I have an index full of `episodes` with this mapping: **PUT test\_episodes** ``` { "settings": { "index": { "number_of_shards": 5, "number_of_replicas": 1 } }, "mappings": { "_doc": { "dynamic": false, "properties": { "id": { "type": "keyword" }, "podcastID": { "type": "keyword" }, "createdAt": { "type": "date", "format": "date_time_no_millis" } } } } } ``` I want to obtain the latest episodes for a podcast (based on `podcastID`). I have a query that returns all latest episodes (sorted by `createdAt` field). How can I limit this to ONE episode per podcastID? Current query: **GET test\_episodes/\_search** ```auto { "query": { "bool": { "filter": { "bool": { "must": [ { "range": { "createdAt": { "gte": "now-14d/d" } } } ] } } } }, "sort": { "createdAt": { "order": "desc" } } } ``` Result: ``` { "took": 1, "timed_out": false, "_shards": { "total": 5, "successful": 5, "skipped": 0, "failed": 0 }, "hits": { "total": 5, "max_score": null, "hits": [ { "_index": "test_episodes", "_type": "_doc", "_id": "episode-0005", "_score": null, "_source": { "id": "episode-0005", "podcastID": "podcast-0002", "createdAt": "2018-10-29T17:00:00+00:00" }, "sort": [ 1540832400000 ] }, { "_index": "test_episodes", "_type": "_doc", "_id": "episode-0002", "_score": null, "_source": { "id": "episode-0002", "podcastID": "podcast-0001", "createdAt": "2018-10-29T16:00:00+00:00" }, "sort": [ 1540828800000 ] }, { "_index": "test_episodes", "_type": "_doc", "_id": "episode-0004", "_score": null, "_source": { "id": "episode-0004", "podcastID": "podcast-0002", "createdAt": "2018-10-29T16:00:00+00:00" }, "sort": [ 1540828800000 ] }, { "_index": "test_episodes", "_type": "_doc", "_id": "episode-0001", "_score": null, "_source": { "id": "episode-0001", "podcastID": "podcast-0001", "createdAt": "2018-10-29T15:00:00+00:00" }, "sort": [ 1540825200000 ] }, { "_index": "test_episodes", "_type": "_doc", "_id": "episode-0003", "_score": null, "_source": { "id": "episode-0003", "podcastID": "podcast-0002", "createdAt": "2018-10-29T14:00:00+00:00" }, "sort": [ 1540821600000 ] } ] } } ``` **Desired outcome result:** Only `episode-0005` and `episode-0002` should be returned. Thanks! Christian ---
**Author:** ![gbrown](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/gbrown/32/34482_2.png) [@gbrown](https://discuss.elastic.co/u/gbrown)\ **Post date:** [October 29, 2018, 5:14pm UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/2 "2018-10-29T17:14:18Z")
Hi Christian! You'll need to use a [Terms aggregation](https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-aggregations-bucket-terms-aggregation.html) to bucket by `podcastID`, then a [Top Hits](https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-aggregations-metrics-top-hits-aggregation.html) subaggregation, sorted by `createdAt` and `size: 1`. That will give you the newest episode for each podcast. ---
**Author:** ![cweinberger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cweinberger/32/33147_2.png) [@cweinberger](https://discuss.elastic.co/u/cweinberger)\ **Post date:** [October 29, 2018, 5:46pm UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/3 "2018-10-29T17:46:50Z")
Hi Gordon, Thanks for your help! I am able to create the buckets as advised; but how can I order them (the buckets) by their episode's date? **GET test\_episodes/\_search** ```auto { "size": 0, "aggs": { "by_podcast": { "terms" : { "field" : "podcastID" }, "aggs": { "latest_episodes": { "top_hits": { "sort" : [ { "createdAt" : { "order" : "desc" } } ], "_source": { "includes": [ "*" ] }, "size": 1 } } } } } } ``` This will return the **latest episode** for each **podcastID**. How can I order the buckets now by the `createdAt` date of their `episode`? Thanks again 🙂 Christian ---
**Author:** ![gbrown](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/gbrown/32/34482_2.png) [@gbrown](https://discuss.elastic.co/u/gbrown)\ **Post date:** [October 29, 2018, 5:58pm UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/4 "2018-10-29T17:58:21Z")
Ah! I didn't realize that was part of it. Since you can't access data from Top Hits in a pipeline aggregation, you'll have to _also_ use a [Max aggregation](https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-aggregations-metrics-max-aggregation.html) as a subaggregation of the Terms aggregation to bubble up the most recent date. Then, you can use a [Bucket Sort pipeline aggregation](https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-aggregations-pipeline-bucket-sort-aggregation.html) to sort the buckets by the newest creation date found in the Max aggregation above. ---
**Author:** ![cweinberger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cweinberger/32/33147_2.png) [@cweinberger](https://discuss.elastic.co/u/cweinberger)\ **Post date:** [October 30, 2018, 6:49am UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/5 "2018-10-30T06:49:18Z")
Thanks Gordon! It seems to work for me as suggested: **GET test\_episodes/\_search** ```auto { "size": 0, "aggs": { "by_podcast": { "terms": { "field": "podcastID" }, "aggs": { "latest_episodes": { "top_hits": { "sort": [ { "createdAt": { "order": "desc" } } ], "_source": { "includes": [ "*" ] }, "size": 1 } }, "recentDate": { "max": { "field": "createdAt" } }, "podcasts_bucket_sort": { "bucket_sort": { "sort": [ { "recentDate": { "order": "desc" } } ] } } } } } } ``` Have a nice week, Christian ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [November 27, 2018, 7:02am UTC](https://discuss.elastic.co/t/limit-search-result-based-on-a-field/154476/6 "2018-11-27T07:02:31Z")
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