elasticsearch/docs/reference/query-languages/sql/sql-functions-system.md

mapped_pages
https://www.elastic.co/guide/en/elasticsearch/reference/current/sql-functions-system.html

System functions [sql-functions-system]

These functions return metadata type of information about the system being queried.

DATABASE [sql-functions-system-database]

DATABASE()

Input: none

Output: string

Description: Returns the name of the database being queried. In the case of Elasticsearch SQL, this is the name of the Elasticsearch cluster. This function should always return a non-null value.

SELECT DATABASE();

   DATABASE
---------------
elasticsearch

USER [sql-functions-system-user]

USER()

Input: none

Output: string

Description: Returns the username of the authenticated user executing the query. This function can return null in case security is disabled.

SELECT USER();

     USER
---------------
elastic