# \_field\_names aggregation with sub-aggregation

**URL:** <https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974>\
**Category:** Elasticsearch\
**Created:** [October 1, 2016, 12:05am UTC](https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974 "2016-10-01T00:05:05Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![velcro](https://avatars.discourse-cdn.com/v4/letter/v/ecb155/32.png) [@velcro](https://discuss.elastic.co/u/velcro)\
**Post date:** [October 1, 2016, 12:05am UTC](https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974/1 "2016-10-01T00:05:05Z")

</div>

After using terms on `_field_names`, I want to sub-aggregation on each field. For each field, I want to know if it contained a non-null value (e.g. using missing, or exists). I do not know how to tell the sub-aggregation to aggregated on itself. I need a way to do this since I didn't specify any fields.

This is what I have. It's wrong.

```
GET _search
{ "size": 0,
    "query": {
        "term": {"property": "TGC"}
    },
    "aggs": {
        "try": {
            "terms": {
                "field": "_field_names",
                "size": 0
            },
            "aggs": {
                "a_counting_sub_agg": {
                    "missing" : { "field" : "_field_names" }
                }
            }
        }
    }
}

```

Here are examples of what I want

Ex.A

```
GET _search
{ "size": 0,
    "query": {
        "term": {"property": "TGC"}
    },
    "aggs": {
        "try": {
            "terms": {
                "field": "_field_names",
                "size": 0
            },
            "aggs": {
                "a_counting_sub_agg": {
                    "missing" : { "field" : "the_current_field.value" }
                }
            }
        }
    }
}

```

Ex.B

```
GET _search
{ "size": 0,
    "query": {
        "term": {"property": "TGC"}
    },
    "aggs": {
        "try": {
            "terms": {
                "field": "_field_names",
                "size": 0
            },
            "aggs": {
                "a_counting_sub_agg": {
                    "term" : { "some_property_every_field_has" : "that_property.value" }
                }
            }
        }
    }
}

```

My desired output would resemble the following  
_// used to include some comments_

```
"aggregations": {
   "try": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0, // should this change??
      "buckets": [
         {
            "key": "bookingDate",
            "doc_count": 7142,
            "a_counting_sub_agg": {
               "doc_count": 10 // As in, 10 records had a "missing" bookingDate
            }
         },
         {
            "key": "checkinDate",
            "doc_count": 7142,
            "a_counting_sub_agg": {
               "doc_count": 0
            }
         },
         {
            "key": "checkoutDate",
            "doc_count": 7142,
            "a_counting_sub_agg": {
               "doc_count": 20 // Means 20 docs had no value for checkoutDate.
            }
         },
         etc...

```

I feel like there is some special keyword I don't know to make this happen. How do I pay attention to the current field, and whether or not is has a value of some sort? For every field in my index, I'm trying to see the count of how many had/didn't have values.

---

<div class="post-metadata">

**Author:** ![colings86](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/colings86/32/44960_2.png) [@colings86](https://discuss.elastic.co/u/colings86)\
**Post date:** [October 3, 2016, 8:12am UTC](https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974/2 "2016-10-03T08:12:06Z")

</div>

Unfortunately you cannot current access the key of the bucket from a sub-aggregation so what you want to do it not currently possible in a single request.

You could achieve this in two requests by using the terms aggregation on the `_field_names` field in a first request, and then sending a second request that has a missing aggregation for each field name returned from the first request.

---

<div class="post-metadata">

**Author:** ![velcro](https://avatars.discourse-cdn.com/v4/letter/v/ecb155/32.png) [@velcro](https://discuss.elastic.co/u/velcro)\
**Post date:** [October 10, 2016, 7:35pm UTC](https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974/3 "2016-10-10T19:35:56Z")

</div>

Thanks for your feedback. I think I found the solution. The sub-agg may not be needed.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 10:13pm UTC](https://discuss.elastic.co/t/-field-names-aggregation-with-sub-aggregation/61974/4 "2017-07-05T22:13:33Z")

</div>