Arithmetic operations with fields

Question

Is it possible to query the result of a subtraction between two fields?

E.g. There are two fields: "start", "end". I would like documents with end - start > 10.

Can this be done directly or the only way to do is to create a new field while loading the documents with this difference?

Answer 1

You can use script filters using the scripting syntax explained in the scripting documentation.

For your specific issue, you might do something like

{
  "query": {
    "filtered": {
      "query": {
        "match_all": {}
      },
      "filter": {
        "script": {
          "script": "doc['end'].value - doc['start'].value > 10"
        }
      }
    }
  }
}

where you can replace the match_all query with your own.

As it's probably clear from the code above, you can access specific fields in your document with the sintax doc['field'] and apply specific functions to their values. In this case, .value (without parenthesis) returns the value of the field itself.