WITH dags as(
  SELECT dag_id
  FROM dag
  WHERE is_paused is False
),

rate as (
  SELECT dag_id,
  SUM(CASE WHEN state='success' THEN 1 ELSE 0 END)*1.0/COUNT(*) as success_rate
  FROM dag_run
  GROUP BY dag_id
)
SELECT rate.*
FROM rate
RIGHT JOIN dags on dags.dag_id = rate.dag_id
ORDER BY rate.dag_id;