Is there a way to build an Elastic query with changing search values?

Question

I want to use Elastic in PHP to process a search request from my website. For example, I have the search parameter

name
age
height
weight.

But it should not be necessary to always search for all parameters.

So it could be that only (name AND age) have values and (height AND weight) have not.

Is there a way to build one query with flexible/changing input values?

The query below would not work when there are no search values for (height AND weight).

{
  "query": {
    "bool": {
      "should": [
        { "match": { "name.keyword": "Anna" } },
        { "match": { "age": "30" } },
        { "match": { "height": "180" } },
        { "match": { "weight": "70" } }
      ]
    }
  }
}

`should` will return true if _any_ of the criteria match (name is "Anna" OR age is 30 OR height is 180 OR weight is 70). Is that what you want? If you want _all_ the criteria to match (AND query), you should use `must` instead of `should`. — markusk, Jul 26 '22 at 12:54

Val · Accepted Answer · 2022-07-27T10:22:37.533

2

Search templates to the rescue:

POST _scripts/my-search-template
{
  "script": {
    "lang": "mustache",
    "source": """
    {
      "query": {
        "bool": {
          "should": [
            {{#name}}
             { "match": { "name.keyword": "{{name}}" } },
            {{/name}}
            {{#age}}
             { "match": { "age": "{{age}}" } },
            {{/age}}
            {{#height}}
             { "match": { "height": "{{height}}" } },
            {{/height}}
            {{#weight}}
             { "match": { "weight": "{{weight}}" } },
            {{/weight}}
             { "match_none": { } }
          ]
        }
      }
    }
    """
  }
}

Note that since you don't know how many criteria you have, the last condition is always false and is only there to make sure the JSON is valid (i.e. the last comma doesn't stay dangling)

You can then run your query like this:

POST my-index/_search/template
{
  "id": "my-search-template",
  "params": {
    "name": "Anna",
    "age": 30
  }
}

edited Jul 27 '22 at 10:22

answered Jul 26 '22 at 11:21

Val

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If you want a condition that is always false, [match_none](https://www.elastic.co/guide/en/elasticsearch/reference/8.3/query-dsl-match-all-query.html#query-dsl-match-none-query) might be a better choice. – markusk Jul 26 '22 at 12:14
@markusk Good point! – Val Jul 26 '22 at 12:19
Works perfectly for me... Can you update your question with the commands you've run? – Val Jul 27 '22 at 10:23
What does the """ behind source mean? – Hella Koe Jul 27 '22 at 10:34
You need to copy/paste and run this in Dev Tools. `""" ... """` is supported in Kibana to store non-JSON content, i.e. the search template. – Val Jul 27 '22 at 10:43
Thank you! Now it also runs perfectly for me! – Hella Koe Jul 27 '22 at 11:05

score 0 · Answer 2 · answered Jul 26 '22 at 10:49

You need to handle in your application that constructs your Elasticsearch query and its very easy to do it in the application as you know what all search parameter value you got from UI, if they are not null than only includes those fields in your Elasticsearch query.

Elasticsearch doesn't support if...else like condition in query.

score 0 · Answer 3 · answered Jul 26 '22 at 12:16

Tldr;

They are multiple way to address your problem in Elasticsearch.

You could be playing with the parameter minimum_should_match

You could be using template queries with conditions.

You could also perform more complex bool queries, that enumerate the possibilities for a match.

You could also use scripts to program the logic you want to see.

Minimum should match

POST /_bulk
{"index":{"_index":"73121817"}}
{"name": "ana", "age": 1, "height": 180, "weight": 70}
{"index":{"_index":"73121817"}}
{"name": "jack", "height": 180, "weight": 70}
{"index":{"_index":"73121817"}}
{"name": "emma", "age": 1, "weight": 70}
{"index":{"_index":"73121817"}}
{"name": "william", "age": 1, "height": 180}
{"index":{"_index":"73121817"}}
{"name": "jenny", "weight": 70}
{"index":{"_index":"73121817"}}
{"name": "marco", "age": 1}
{"index":{"_index":"73121817"}}
{"name": "giulia", "height": 180}
{"index":{"_index":"73121817"}}
{"name": "paul"}


GET 73121817/_search
{
  "query": {
    "bool": {
      "should": [
        { "match": { "name.keyword": "Anna" } },
        { "match": { "age": "30" } },
        { "match": { "height": "180" } },
        { "match": { "weight": "70" } }
      ],
      "minimum_should_match": 2
    }
  }
}

with the minimum should match set to 2 only 2 documents are returned ana and jack

Template queries

Well Val's answer is quite complete

You could also refer to the doc

Complex queries

Refer to the so post behind the link

Scripted queries

GET 73121817/_search
{
  "query": {
    "bool": {
      "filter": {
        "script": {
          "script": """
            return (!doc["name.keyword"].empty && !doc["age"].empty);
          """
        }
      }
    }
  }
}