Elasticsearch - SQL Access:
It is a component that allows SQL-like queries to be executed in real-time against Elasticsearch.
You can think of Elasticsearch SQL as a translator, one that understands both SQL and Elasticsearch
and makes it easy to read and process data in real-time, at scale by leveraging Elasticsearch capabilities.

Advantages of Elasticsearch SQL
It has native integration − Each and every query is efficiently executed against the
                            relevant nodes according to the underlying storage.

No external parts − No need for additional hardware, processes, runtimes or libraries to query Elasticsearch.

Lightweight and efficient − it embraces and exposes SQL to allow proper full-text search, in real-time.

E.g:

GET /_sql?format=txt
{
  "query": """
  SELECT moref, name, dsInfo.name FROM "poc-vms"
  """
}

Response:
     moref     |     name      |  dsInfo.name
---------------+---------------+---------------
vm-1           |vm1            |Datastore1
vm-2           |vm2            |Datastore1
vm-3           |vm3            |Datastore2
vm-4           |vm4            |Datastore2
vm-5           |vm5            |Datastore3
vm-6           |vm6            |Datastore3
vm-7           |vm7            |Datastore4


GET /_sql?format=txt
{
  "query": """
  SELECT * FROM "users" where id>2
  """
}

      Age      |      id       |     name
---------------+---------------+---------------
25             |3              |Aman--Edit1
26             |4              |Aakash--Edit1
