Similar functionality already exists in some SQL implementations, notably DuckDB:

  create table macro author_books() as   
  (
    select
        a.name as author,
        b.title,
    from
        a
    inner join
        b on b.author_id = a.author_id
  );

is the same as the example in the article and it is called like:

  with a as (...),
       b as (...)
       from author_books();

https://duckdb.org/docs/sql/statements/create_macro.html#tab...