Find documents with empty string value on elasticsearch

Question

I\'ve been trying to filter with elasticsearch only those documents that contains an empty string in its body. So far I\'m having no luck.

Before I go on, I should

Answer 1

I didn't manage to search for empty strings in a text field. However it seems to work with a field of type keyword. So I suggest the following:

    delete /test_idx

    put test_idx
    {
      "mappings" : {
        "testMapping": {
          "properties" : {
            "tag" : {"type":"text"},
            "content" : {"type":"text",
                         "fields" : {
                           "x" : {"type" : "keyword"}
                         }
            }
          }
        }
      }
    }

put /test_idx/testMapping/1
{
  "tag": "null"
}

put /test_idx/testMapping/2
{
  "tag": "empty",
  "content": ""
}

GET /test_idx/testMapping/_search
{
   "query" : {
     "match" : {"content.x" : ""}}}
             }
}