Elasic Existed Query Not working About Empty String

Question

According to Official 7.x document Link

While a field is deemed non-existent if the JSON value is null or [], these values will indicate the field does exist:

Empty strings, such as "" or "-" Arrays containing null and another value, such as [null, "foo"] A custom null-value, defined in field mapping

However, My es not consider "" as not existed. Here is my Data:

"_source" : {
      "chat_msg" : {
        "action" : "send",
        "from" : "t",
        "msgid" : "6505946507184390735_161_external",
        "msgtime" : 1623396135015,
        "msgtype" : "text",
        "roomid" : "",

Now, When I do Query As :

GET enterprise_chat_data/_search
{
  "query": {
    "bool": {
      "must_not": [
        {
          "exists": {
            "field": "chat_msg.roomid"
          }
        }
      ]
    }
  }
}

Result:

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 2,
    "successful" : 2,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 0,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  }
}

It Hit Nothing. Am I Wrong About Something?

Bhavya · Accepted Answer · 2021-06-11 08:09:53Z

1

I think you have misunderstood the documentation. In the documentation, it is written that if a field have value as empty strings, such as "" or "-", then that field will be considered to be existing.

Due to this when you are querying for must_not exists query for "chat_msg.roomid" field, you are getting empty results, as in the data you have indexed the value of "chat_msg.roomid" field as ""

Update 1:

You can use term query to search for documents having field value of chat_msg.roomid as ""

{
  "query": {
    "term": {
      "chat_msg.roomid.keyword": ""
    }
  }
}

edited Jun 11, 2021 at 8:09

answered Jun 11, 2021 at 7:44

Bhavya

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1 Comment

En Xie Over a year ago

omy.... eye... My I Ask How to find all roomId which is ""?

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