Measure API Availability Against an SLO

SELECT
  date_trunc('day', timestamp_utc) AS day,
  service,
  SUM(CASE WHEN slo_eligible THEN 1 ELSE 0 END) AS eligible_requests,
  SUM(CASE WHEN slo_eligible AND slo_good THEN 1 ELSE 0 END)
    AS good_requests,
  100.0 * SUM(CASE WHEN slo_eligible AND slo_good THEN 1 ELSE 0 END)
    / NULLIF(SUM(CASE WHEN slo_eligible THEN 1 ELSE 0 END), 0)
    AS availability_pct,
  99.9 AS objective_pct
FROM api_requests
WHERE timestamp_utc >= now() - INTERVAL '30 days'
GROUP BY date_trunc('day', timestamp_utc), service
HAVING SUM(CASE WHEN slo_eligible THEN 1 ELSE 0 END) > 0
ORDER BY day, service;