No puedo agrupar cadenas de varios registros en postgresql

[death_nemesis]

Prueba utilizando sub querys te dejo un ejemplo

Código SQL:

SELECT n1.name, n1.author_id, count_1, 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 id, author_id, COUNT(1) AS total_count
              FROM names
              GROUP BY id, author_id) n2
  ON (n2.id = n1.id AND n2.author_id = n1.author_id)