WITH answer AS (SELECT u.id AS an_user_id,
                  p.id AS answer_id,
                  p.parent_id AS post_id,
                  u.creation_date + INTERVAL '1 months' AS first_month,
                  p.creation_date AS dt_answer
           FROM stackoverflow.posts AS p
           LEFT OUTER JOIN stackoverflow.users AS u ON p.user_id = u.id
           LEFT OUTER JOIN stackoverflow.post_types AS pt ON p.post_type_id = pt.id
           WHERE pt.type = 'Answer'),

      hundred_answer AS (SELECT a.an_user_id,
                                COUNT(p.user_id) AS cnt
                         FROM answer AS a
                         INNER JOIN stackoverflow.posts AS p ON a.post_id = p.id
                         WHERE a.dt_answer < a.first_month
                         GROUP BY a.an_user_id
                         HAVING COUNT(a.answer_id) > 100)

SELECT u.display_name,
       ha.cnt
FROM hundred_answer AS ha
INNER JOIN stackoverflow.users AS u ON ha.an_user_id = u.id
ORDER BY u.display_name ASC;