# Elastic-Index Join

**URL:** <https://discuss.elastic.co/t/elastic-index-join/317474>\
**Category:** Elasticsearch\
**Tags:** reindex\
**Created:** [October 26, 2022, 6:38am UTC](https://discuss.elastic.co/t/elastic-index-join/317474 "2022-10-26T06:38:44Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![balaa](https://avatars.discourse-cdn.com/v4/letter/b/85e7bf/32.png) [@balaa](https://discuss.elastic.co/u/balaa)\
**Post date:** [October 26, 2022, 6:38am UTC](https://discuss.elastic.co/t/elastic-index-join/317474/1 "2022-10-26T06:38:44Z")

</div>

Hi Team,

My requirement is to join two index as mentioned below.Is it possible? if yes how to achieve it.

Index 1:  
{  
"A": 1,  
"B": "Sam",  
"C": 1234  
}  
Index 2:  
{  
"C": 1234,  
"D": "elastic",  
"E": "Support"  
}  
Final:  
{  
"A": 1,  
"B": "Sam",  
"C": 1234,  
"D": "elastic",  
"E": "Support"  
}

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 26, 2022, 6:55am UTC](https://discuss.elastic.co/t/elastic-index-join/317474/2 "2022-10-26T06:55:40Z")

</div>

Welcome to our community! 😃

You could do that with a reindex and an ingest pipeline with an enrich processor.

---

<div class="post-metadata">

**Author:** ![balaa](https://avatars.discourse-cdn.com/v4/letter/b/85e7bf/32.png) [@balaa](https://discuss.elastic.co/u/balaa)\
**Post date:** [October 26, 2022, 11:52am UTC](https://discuss.elastic.co/t/elastic-index-join/317474/3 "2022-10-26T11:52:08Z")

</div>

Thanks Warkolm!!!Can you elaborate more or with samples?

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<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [November 1, 2022, 2:48am UTC](https://discuss.elastic.co/t/elastic-index-join/317474/4 "2022-11-01T02:48:21Z")

</div>

My mistake here, a transform works best when you already have the data in Elasticsearch. Here's an example;

````auto
PUT index1/_doc/1
{
"A": 1,
"B": "Sam",
"C": 1234
}

PUT index2/_doc/1
{
"C": 1234,
"D": "elastic",
"E": "Support"
}

PUT _transform/my-join
{
  "source": {
    "index": [
      "index1",
      "index2"
    ]
  },
  "dest": {
    "index": "joined-index"
  }, 
  "pivot": {
    "group_by": {
      "id": {
        "terms": {
          "field": "C"
        }
      }
    },
    "aggregations": {
      "combineFields": {
      "scripted_metric": {
        "init_script": "state.join = new HashMap()",
        "map_script": """
          String[] fields = new String[] {'A', 'B', 'C', 'D', 'E'};
          for (field in fields) {
            if (doc.containsKey(field + ".keyword")) {
              state.join.put(field, doc[field + ".keyword"]);
            } else if (doc.containsKey(field)) {
              state.join.put(field, doc[field]);
            }
          }
        """,
        "combine_script": "return state.join",
        "reduce_script": """
          String[] fields = new String[] {'A', 'B', 'C', 'D', 'E'};
          Map combined=new HashMap();
          for (state in states) {
            for (field in fields) {
              if (state.containsKey(field)) {
                combined.put(field, state[field].get(0));
              }
            }
          }
          return combined;
        """
      }
    }
    }
  }
}

POST _transform/my-join/_start

GET joined-index/_search
{
  "took": 0,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 1,
      "relation": "eq"
    },
    "max_score": 1,
    "hits": [
      {
        "_index": "joined-index",
        "_id": "ALnOexvkEM03Dun-taspfc0AAAAAAAAA",
        "_score": 1,
        "_source": {
          "combineFields": {
            "A": 1,
            "B": "Sam",
            "C": 1234,
            "D": "elastic",
            "E": "Support"
          },
          "id": 1234
        }
      }
    ]
  }
}
```
````

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<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [November 1, 2022, 2:48am UTC](https://discuss.elastic.co/t/elastic-index-join/317474/5 "2022-11-01T02:48:52Z")

</div>

You can also do this in a search, but it won't be stored into another index like a transform;

```auto
GET index1,index2/_search
{
  "aggregations": {
    "combineFields": {
      "scripted_metric": {
        "init_script": "state.join = new HashMap()",
        "map_script": """
          String[] fields = new String[] {'A', 'B', 'C', 'D', 'E'};
          for (field in fields) {
            if (doc.containsKey(field + ".keyword")) {
              state.join.put(field, doc[field + ".keyword"]);
            } else if (doc.containsKey(field)) {
              state.join.put(field, doc[field]);
            }
          }
        """,
        "combine_script": "return state.join",
        "reduce_script": """
          String[] fields = new String[] {'A', 'B', 'C', 'D', 'E'};
          Map combined=new HashMap();
          for (state in states) {
            for (field in fields) {
              if (state.containsKey(field)) {
                combined.put(field, state[field].get(0));
              }
            }
          }
          return combined;
        """
      }
    }
  }
}

```

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<div class="post-metadata">

**Author:** ![balaa](https://avatars.discourse-cdn.com/v4/letter/b/85e7bf/32.png) [@balaa](https://discuss.elastic.co/u/balaa)\
**Post date:** [November 3, 2022, 5:59pm UTC](https://discuss.elastic.co/t/elastic-index-join/317474/6 "2022-11-03T17:59:36Z")

</div>

> [@warkolm](#):
>
> ```auto
> GET joined-index/_search
> {
> "took": 0,
> "timed_out": false,
> "_shards": {
> "total": 1,
> "successful": 1,
> "skipped": 0,
> "failed": 0
> },
> "hits": {
> "total": {
> "value": 1,
> "relation": "eq"
> },
> "max_score": 1,
> "hits": [
> {
> "_index": "joined-index",
> "_id": "ALnOexvkEM03Dun-taspfc0AAAAAAAAA",
> "_score": 1,
> "_source": {
> "combineFields": {
> "A": 1,
> "B": "Sam",
> "C": 1234,
> "D": "elastic",
> "E": "Support"
> },
> "id": 1234
> }
> }
> ]
> }
> }
> 
> ```

Awesome brother...exactly this is what looking..you made my day

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [November 3, 2022, 10:04pm UTC](https://discuss.elastic.co/t/elastic-index-join/317474/7 "2022-11-03T22:04:02Z")

</div>

Thanks @xeraa too.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 1, 2022, 10:04pm UTC](https://discuss.elastic.co/t/elastic-index-join/317474/8 "2022-12-01T22:04:16Z")

</div>

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