WITH step_differences AS ( SELECT feature_id, user_id, step_reached, timestamp, LEAD(timestamp) OVER (PARTITION BY feature_id, user_id ORDER BY step_reached) AS next_timestamp FROM facebook_product_features_realizations ), time_differences AS ( SELECT feature_id, EXTRACT(EPOCH FROM (next_timestamp - timestamp)) AS time_diff FROM step_differences WHERE next_timestamp IS NOT NULL ) SELECT feature_id, AVG(time_diff) AS avg_time_in_seconds FROM time_differences GROUP BY 1 ORDER BY 1