WITH trial_plan AS 
  (SELECT 
    customer_id, 
    start_date AS trial_date
  FROM foodie_fi.subscriptions
  WHERE plan_id = 0
),
-- Filter results to customers at pro annual plan = 3
annual_plan AS
  (SELECT 
    customer_id, 
    start_date AS annual_date
  FROM foodie_fi.subscriptions
  WHERE plan_id = 3
),
-- Sort values above in buckets of 12 with range of 30 days each
bins AS 
  (SELECT 
    WIDTH_BUCKET(ap.annual_date - tp.trial_date, 0, 360, 12) AS     avg_days_to_upgrade
  FROM trial_plan tp
  JOIN annual_plan ap
    ON tp.customer_id = ap.customer_id)
  
SELECT 
  ((avg_days_to_upgrade -1) * 30 || ' - ' ||   (avg_days_to_upgrade) * 30) || ' days' AS breakdown, 
  COUNT(*) AS customers
FROM bins
GROUP BY avg_days_to_upgrade
ORDER BY avg_days_to_upgrade;