SQL having clause question...

# Person has_many cards has_many transaction_feeds.
# I would like to find all of the people with at least one transaction feed with the is_ach bool set to true:
SELECT DISTINCT(people.id) AS person_id FROM `people`
  INNER JOIN `cards` ON cards.person_id = people.id
  INNER JOIN `transaction_feeds` ON transaction_feeds.card_id = cards.id
  WHERE (transaction_feeds.is_ach = 1)
  GROUP BY person_id
  HAVING COUNT(transaction_feeds.id) > 0;

# This works.
# I would like to find all of the people with no transaction feeds that have that is_ach bool set to true.
# I don't know how to do this.

# NAIVE ATTEMPT ONE:
SELECT DISTINCT(people.id) AS people_id FROM `people`
  INNER JOIN `cards` ON cards.person_id = people.id
  LEFT JOIN `transaction_feeds` ON transaction_feeds.card_id = cards.id
  WHERE (transaction_feeds.is_ach = 1)
  GROUP BY person_id
  HAVING COUNT(transaction_feeds.id) = 0;
Empty set (0.42 sec)

USE THIS:

SELECT DISTINCT(people.id) AS people_id FROM `people`
  INNER JOIN `cards` ON cards.person_id = people.id
  LEFT JOIN `transaction_feeds` ON transaction_feeds.card_id = cards.id AND transaction_feeds.is_ach = 1
  GROUP BY person_id
  HAVING COUNT(transaction_feeds.id) = 0;