Problem with aggs queries returning null?

[JamesD_7 (James Drinkard)]

Hello,
I'm having trouble getting a simple aggs query to return data.

GET mydata1/_search
{
  "aggs": {
    "avg_num_days": {
     "avg": {
       "field": "myField"
     }
    }
  }
}

I was getting an error:

"error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "Field [myField] of type [keyword] is not supported for aggregation [avg]"
      }

I did some searches on the internet and found I needed this field to be a long, not a keyword as aggs don't work on keywords. I deleted the index and tried to do a PUT explicit mapping, but since the index is gone that wont work. I know I have to get this declared before the index is created, but what is the proper way change the datatype for this single field so I can run aggs against it?

All the other fields are automatically mapped properly by Elasticsearch when I import the data, a single CVS, standalone file that I upload to Kibana.

Thank you,
James

[hendry.lim (Hendry)]

You will have to explicitly specify the field type in the index mappings either during index creation type or in an index template.

If you use Kibana to upload a CSV file, there is a box that allows you to specify the index mappings.