queries.sql

-- users
select u.*
from   users u
where  u.id = 123
order by u.id;

-- books
select count(*) as b_cnt,
       b.user_id
from   books b
group by b.user_id
order by b_cnt desc;

-- users.join(books).select_append(books[:b_cnt])
select u.*,
       b.b_cnt
from   users u
inner join books b
on     b.user_id = u.id
where  u.id = 123
group by b.user_id
order by u.id, b.b_cnt desc;

-- users.join(books).select_append(books[:b_cnt])
select u.*
from   users u
inner join (
  select count(*) as b_cnt,
         b.user_id
  from   books b
  group by b.user_id
  order by b_cnt desc) b
on     b.user_id = u.id
where  u.id = 123
order by u.id;