How to do a Postgresql subquery in select clause with join in from clause like SQL Server?

Question

I am trying to write the following query on postgresql:

select name, author_id, count(1), 
    (select count(1)
    from names as n2
    where n2.id = n1.id
             


        

Answer 1

select n1.name, n1.author_id, cast(count_1 as numeric)/total_count
  from (select id, name, author_id, count(1) as count_1
          from names
          group by id, name, author_id) n1
inner join (select distinct(author_id), count(1) as total_count
              from names) n2
  on (n2.author_id = n1.author_id)
Where true

used distinct if more inner join, because more join group performance is slow