osquery exposes an operating system as a high-performance relational database. This allows you to write SQL-based queries to explore operating system data. With osquery, SQL tables represent abstract concepts such as running processes, loaded kernel modules, open network connections, browser plugins, hardware events or file hashes.
SQL tables are implemented via a simple plugin and extensions API. A variety of tables already exist and more are being written: https://osquery.io/schema. To best understand the expressiveness that is afforded to you by osquery, consider the following SQL queries:
SELECT * FROM users;