Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!
https://www.elastic.co/guide/en/elasticsearch/reference/2.1/setup-service.html
SQL Support
- Elasticsearch supports SQL syntax starting from version 6.3. There is also an unofficial SQL support of Elasticsearch by NLPchina/elasticsearch-sql
Links
https://www.elastic.co/downloads
Aggregation
The after_key is equals to the last bucket returned in the response before any filtering that could be done by Pipeline aggregations. If all buckets are filtered/removed by a pipeline aggregation, the after_key will contain the last bucket before filtering.
References
https://logz.io/blog/elasticsearch-sql-support/
https://medium.com/@mustafaakin/previewing-elasticsearch-6-3-sql-feature-2d3a1d60cab4