Need cardinality aggregation to be supported

Question

Need cardinality aggregation to be supported

standino opened this issue 8 years ago · comments

Please help to implement cardinality-aggregation. Thanks.

Finding Distinct Countsedit
The first approximate aggregation provided by Elasticsearch is the cardinality metric. This provides the cardinality of a field, also called a distinct or unique count. You may be familiar with the SQL version:

SELECT COUNT(DISTINCT color)
FROM cars

https://www.elastic.co/guide/en/elasticsearch/guide/current/cardinality.html
https://www.elastic.co/guide/en/elasticsearch/reference/2.2/search-aggregations-metrics-cardinality-aggregation.html

Corne Versloot · Answer 1 · Sat Mar 25 2017 00:01:33 GMT+0800 (China Standard Time)

Would be nice to include it in the driver indeed. It seems the Elastic side is relatively easy but it has to be parsed and interpreted correctly first. Feel free to give it a go and create a pull request for it.

Corne Versloot · Answer 2 · Sun Mar 26 2017 20:19:52 GMT+0800 (China Standard Time)

Added support for cardinality aggregations in version 0.9.2.4 (works for Elasticsearch versions 2.X.X). I havent been able to test it thoroughly so let me know if anything is wrong with the current implementation.

Marcelo Dias · Answer 3 · Mon Apr 03 2017 21:07:41 GMT+0800 (China Standard Time)

Hi,
Thank you for the good work with this driver.
We'd like to use this feature with Pentaho. But we are getting a message in the logs:
Unable to combine COUNT DISTINCT with a normal SELECT within a single query
Is there any plan to enable these kind of queries?
select company, count(distinct empId) from payments group by company