EXPLAIN
SELECT p.id, p.title, a.name
FROM posts AS p
JOIN authors AS a ON a.id = p.author_id
WHERE p.status = 'publish'
  AND p.published_at >= CURRENT_DATE - INTERVAL '30 day'
ORDER BY p.published_at DESC
LIMIT 50;
-- PostgreSQL testing only: EXPLAIN (ANALYZE, BUFFERS) ...
-- MySQL testing only: EXPLAIN ANALYZE ...