instruction: % of questions edited after close (graph based on Date Closed).
response: SELECT LAST_DATE_OF_MONTH(ClosedDate) AS Closed, 1.0 * SUM(CASE WHEN LastEditDate > ClosedDate THEN 1 ELSE 0 END) / COUNT(*) AS "%edit_after_close" FROM Posts WHERE NOT ClosedDate IS NULL AND PostTypeId = 1 GROUP BY LAST_DATE_OF_MONTH(ClosedDate) ORDER BY LAST_DATE_OF_MONTH(ClosedDate)