ElasticSearch - Create Query That Show Different Properties Between Two Indexes

Question

I am trying to create an elastic query that will show non-common properties between two indexes. Say the first index is:

{
  "myFirstIndex" : {
    "mappings" : {
      "properties" : {
        "CAT" : {
          "type" : "keyword",
          "ignore_above" : 256
        },
        "DATE_OF_BIRTH" : {
          "type" : "date",
          "format" : "dateOptionalTime"
        },
        "ID" : {
          "type" : "keyword",
          "ignore_above" : 256
        },
        "NAME" : {
          "type" : "text"
        },
        "timestamp" : {
          "type" : "date",
          "format" : "dateOptionalTime"
        }
      }
    }
  }
}

, and the second was is:

{
  "mySecondIndex" : {
    "mappings" : {
      "properties" : {
        "CAT" : {
          "type" : "keyword",
          "ignore_above" : 256
        },
        "DATE_OF_BIRTH" : {
          "type" : "date",
          "format" : "dateOptionalTime"
        },
        "ID" : {
          "type" : "keyword",
          "ignore_above" : 256
        }
      }
    }
  }
}

I have never done a query across indexes so I am not sure how to do this. I don't care much about whether the properties have nested characteristics. For my purposes, finding the appropriate common properties at a base level is sufficient.

Grateful for any assistance. Thank you

Answer 1

(based off your clarifications) you can't do that natively in Elasticsearch

you'd need to run the queries from some code and then compare the two indices in said code