Elasticsearch query on array index

Question

How do I query/filter by index of an array in elasticsearch?

I have a document like this:-

PUT /edi832/record/1
{
    "LIN": [ "UP", "123456789" ]
}

I want to search if LIN[0] is "UP" and LIN[1] exists.

Thanks.

Answer 1

This might look like a hack , but then it will work for sure. First we apply token count type along with multi field to capture the the number of tokens as a field. So the mapping will look like this -

{
    "record" : {
        "properties" : {
            "LIN" : {
                "type" : "string",
                "fields" : {
                    "word_count": {
                        "type" : "token_count",
                        "store" : "yes",
                        "analyzer" : "standard"
                    }
                }
            }
        }
    }
}

LINK - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-core-types.html#token_count

So to check if the second field exists , its as easy as checking if this field value is more than or equal to 2. Next we can use the token filter to check if the token "up" exists in position 0. We can use the scripted filter to check this. Hence a query like below should work -

{
  "query": {
    "filtered": {
      "query": {
        "range": {
          "LIN.word_count": {
            "gte": 2
          }
        }
      },
      "filter": {
        "script": {
          "script": "for(pos : _index['LIN'].get('up',_POSITIONS)){ if(pos.position == 0) { return true}};return false;"
        }
      }
    }
  }
}

Advanced scripting - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-advanced-scripting.html

Script filters - http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-script-filter.html