Reference: WITH (CTEs)

For complex queries, with subqueries, aka common table expressions (CTEs) are a good way to structure your query. They help to build small, self-contained logic blocks that can be named. This allows to factor out parts of a query that can be independently developed and verified.

-- All good movies with a high rating
with good_movies as (select * from movies where rating >= 8.0)
select * from good_movies m, producers p
where m.producer_id = p.id;