如何在Elasticsearch索引中搜索值为字段为空数组的文档？

Question

I need to get documents in an elasticseach index which have empty array for a field (which can be nested)?

Doing it the below way is not working

{
  "query": {
    "filter": {
      "script": {
        "script": "doc['arrayField'].length > 0"
      }
    }
  } 
}

or

{
  "query": {
    "bool": { 
      "must": { "match_all": {} },
      "filter": { "term": { "arrayField": [] }}
    }
  } 
}

It seems like I have to use the filter feature, alongwith some script but can't figure out how.

Answer 1

To get documents with the empty array we find the length of the field and see if it's length is less than 1. Please, the working query below.

"query": {
        "bool" : {
            "must" : {
                "script" : {
                    "script" : {
                        "inline": "doc['arrayField'].length < 1",
                        "lang": "painless"
                     }
                }
            }
        }
    }

Let me know if you find any issues.
Thanks