計算 API 錯誤預算消耗率

WITH hourly AS (
  SELECT
    date_trunc('hour', timestamp_utc) AS hour,
    COUNT(*) AS requests,
    SUM(CASE WHEN status_code >= 500 THEN 1 ELSE 0 END) AS bad_requests
  FROM api_requests
  WHERE timestamp_utc >= now() - INTERVAL '24 hours'
    AND environment = 'production'
  GROUP BY date_trunc('hour', timestamp_utc)
)
SELECT
  hour,
  requests,
  bad_requests,
  100.0 * bad_requests / NULLIF(requests, 0) AS error_rate_pct,
  (1.0 * bad_requests / NULLIF(requests, 0)) / 0.001 AS burn_rate
FROM hourly
ORDER BY hour;