-- Useful capability checks before following a database-specific guide.
SELECT VERSION() AS database_version;
SELECT CURRENT_USER AS current_user;
-- PostgreSQL: SHOW server_version; SELECT current_database();
-- MySQL: SHOW VARIABLES LIKE 'version%'; SHOW DATABASES;
-- SQLite: SELECT sqlite_version();
-- Redis is not SQL; use redis-cli INFO server and COMMAND DOCS instead.