LATERAL joins let subqueries reference outer query columns for per-row computation. They replace multiple application-side queries with one efficient database query. Think of LATERAL as a correlated subquery in FROM.
Lateral Subqueries
SELECT u.name, recent.total
FROM users u,
LATERAL (
SELECT total FROM orders
WHERE user_id = u.id
ORDER BY created DESC LIMIT 1
) AS recent
WHERE recent.total > 100;