One row for each association id SQL

one_row.sql

CREATE OR REPLACE VIEW next_episode_ids AS (
  SELECT id, ROW_NUMBER() OVER(PARTITION BY show_id ORDER BY airs_on) AS r
  FROM episodes
  WHERE airs_on >= NOW()
);

CREATE OR REPLACE VIEW next_episodes AS (
  SELECT * FROM episodes WHERE id IN (
    SELECT id FROM next_episode_ids WHERE r = 1
  )
);

SELECT * FROM shows
LEFT JOIN next_episodes ON next_episodes.show_id = shows.id;