Can you refer to and filter on a script field in a query expression, after defining it?

Question

I'm new to ElasticSearch and was wondering, once you define a script field with mvel syntax, can you subsequently filter on, or refer to it in the query body as if it was any other field?

I can't find any examples of this while same time I don't see any mention of whether this is possible on the docs page

http://www.elasticsearch.org/guide/reference/modules/scripting/ http://www.elasticsearch.org/guide/reference/api/search/script-fields/

The book ElasticSearch Server doesn't mention if this is possible or not either

Answer 1

As for 2018 and Elastic 6.2 it is still not possible to filter by fields defined with script_fields, however, you can define custom script filter for the same purpose. For example, lets assume that you've defined the following script field:

{
  "script_fields" : {
    "some_date_fld_year":"doc["some_date_fld"].empty ? null : doc["some_date_fld"].date.year"
  }
}

you can filter by it with

{
  "query": {
    "bool" : {
      "must" : {
        "script" : {
          "script" : {
            "source": " (doc["some_date_fld"].empty ? null : doc["some_date_fld"].date.year) >= 2017",
            "lang": "painless"
          }
        }
      }
    }
  }
}