Count distinct on elastic search

Question

How to achieve count distinct function on elastic search type using sql4es driver?

Select distinct inv_number , count(1) from invoices;

But

Answer 1

Elasticsearch doesn't support deterministic DISTINCT counts (source). It supports only approximate distinct counters like "cardinality". One way to count distincts in a deterministic way is to aggregate them using "terms" and count buckets from result.

Answer 2

Since, the OP is using sql4es jdbc driver, he is asking for a sql query for his use-case :

SELECT COUNT(DISTINCT inv_number) from invoices;

it returns the number of distinct values of the specified column

Answer 3

  {
      "size": 0, 
      "aggs": {
        "total_invoices": {
          "terms": {
            "field": "inv_number" 

        },
        "aggs": {
          "unique_invoiceid": {
            "cardinality": {
              "field": "inv_number"
            }
          }
        }
      }
    }

This will give you the invoice number as key and distict value in unique_invoiceid

Answer 4

This should work to count exact distinct values:

curl -X POST "localhost:9200/invoices/_search?size=0&pretty" -H 'Content-Type: application/json' -d '{
"aggs" : {
    "types_count" : {
      "value_count" : { "field" : "inv_number" }
    },
    "group_by_status": {
      "terms": {
        "field": "inv_number"
      }
    }
}

}'