# Merge fields between documents
**URL:** https://discuss.elastic.co/t/merge-fields-between-documents/303525
**Category:** Elasticsearch
**Tags:** eql-elastic-query-language
**Created:** [April 28, 2022, 2:34pm UTC](https://discuss.elastic.co/t/merge-fields-between-documents/303525 "2022-04-28T14:34:34Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Khaled\_Saidi](https://discuss.elastic.co/u/Khaled_Saidi)
#### Post date: [April 28, 2022, 2:34pm UTC](https://discuss.elastic.co/t/merge-fields-between-documents/303525/1 "2022-04-28T14:34:34Z")
Hi everyone,
I have 2 kinds of docments in an Elasticsearch index.
Document 1:
```auto
{
"_id": "xxxxxxx",
"internal_id": "123456",
"message": "LOREM IPSUM"
}
```
Document 2:
```auto
{
"_id": "yyyyyyy",
"internal_id": "123456",
"date": "2022-04-28",
"method": "GET"
}
```
Is there a way to query the index and have such a result:
```auto
{
"_id": "yyyyyyy",
"internal_id": "123456",
"date": "2022-04-28",
"method": "GET",
"message": "LOREM IPSUM"
}
```
A query that is able to "inject" a field from document 1 into document 2 in its result.
If not possible, how to join on the same field between 2 documents.
Thanx a lot for your help and answers.
Khaled
---
### Author:  [@RabBit\_BR](https://discuss.elastic.co/u/RabBit_BR)
#### Post date: [April 28, 2022, 4:05pm UTC](https://discuss.elastic.co/t/merge-fields-between-documents/303525/2 "2022-04-28T16:05:43Z")
Hi!
I think you should do this merge on the application side but I send the post below, hope it helps.
> [@Combine multiple document into one document with limited Fields ( merging of documents )](https://discuss.elastic.co/t/combine-multiple-document-into-one-document-with-limited-fields-merging-of-documents/231758/6):
>
> You can use a [transform](https://www.elastic.co/guide/en/elasticsearch/reference/7.7/transforms.html) for it. The group\_by must be based on a common criteria, e.g. a common id. For the combining step, you can use a scripted metric, e.g.: "all\_docs": { "scripted\_metric": { "init\_script": "state.docs = []", "map\_script": "state.docs.add(new HashMap(params['\_source']))", "combine\_script": "return state.docs", "reduce\_script": "def docs = []; for (s in states) {for (d in s) { docs.add(d);}}return docs" } } this would create an array with the original do…
---
### Author:  [@Khaled\_Saidi](https://discuss.elastic.co/u/Khaled_Saidi)
#### Post date: [April 29, 2022, 8:01am UTC](https://discuss.elastic.co/t/merge-fields-between-documents/303525/3 "2022-04-29T08:01:45Z")
Hi Andre,
Thank you for this solution. i will try it today..
Hope it works for me.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [May 27, 2022, 8:01am UTC](https://discuss.elastic.co/t/merge-fields-between-documents/303525/4 "2022-05-27T08:01:46Z")
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