# More\_like\_this and fields with empty values (no matches)

**URL:** <https://discuss.elastic.co/t/more-like-this-and-fields-with-empty-values-no-matches/139822>\
**Category:** Elasticsearch\
**Created:** [July 12, 2018, 7:01pm UTC](https://discuss.elastic.co/t/more-like-this-and-fields-with-empty-values-no-matches/139822 "2018-07-12T19:01:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![orogvany](https://avatars.discourse-cdn.com/v4/letter/o/a183cd/32.png) [@orogvany](https://discuss.elastic.co/u/orogvany)\
**Post date:** [July 12, 2018, 7:01pm UTC](https://discuss.elastic.co/t/more-like-this-and-fields-with-empty-values-no-matches/139822/1 "2018-07-12T19:01:14Z")

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I am doing a more\_like\_this query as follows

> "more\_like\_this" : {  
> "fields" : [  
> "title", "keywords", "description"  
> ],  
> "like" : [  
> {  
> "\_index" : "indexName",  
> "\_id" : "12354",  
> "\_type": "Object"  
> }  
> ],  
> "min\_term\_freq" : 1,  
> "max\_query\_terms" : 12  
> }

I notice that if all the fields have values set, I'll get matching results as I expect for similar documents.

However, if my documents have empty string values for lets say the 'description' field, my MLT query always returns 0 values. So, even 3 documents with the same values for 'title','keywords' and all have empty description, I will not get matches.

I'm struggling to find some combination of term selection parameters that just ignores likeness if there is no value for a given field. I'm confused why it would be giving no results. It sounds like from the docs that

> The MLT query simply extracts the text from the input document, analyzes it, usually using the same analyzer at the field, then selects the top K terms with highest tf-idf to form a disjunctive query of these terms.

So fields with no values at all shouldn't affect the query that is given, as the top K terms shouldn't include an empty field, or the empty should at least be ignored? Is there a way to request to see what query is created behind the scenes that may give some insight into where its going wrong?

Any help would be appreciated!

Possibly important: the fields I'm using are analyzed text types. Changing the analyzers seems to affect whether it finds as a match/works on empty, so there may be some weird interaction there. I've tried creating them all using the same analyzer, and still emptyString doesn't appear to match up right.

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<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:** [August 9, 2018, 7:01pm UTC](https://discuss.elastic.co/t/more-like-this-and-fields-with-empty-values-no-matches/139822/2 "2018-08-09T19:01:16Z")

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