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Q&A about the site for practitioners of the art and science of signal, image and video processing

-- The best time to ask questions
-- Look for the minimum value on y-scale:
-- It says when the time between question and answer is minimal.
-- For example

DECLARE @Frequency int = ##Frequency:int?3##
DECLARE @CutOffTime int = ##CutOffTime:int?1440##

;WITH tmp AS
(
  SELECT timeDiff = DATEDIFF(minute, q.CreationDate, a.CreationDate),
         Period = CASE @Frequency
           WHEN 1 THEN DATEPART("hour", q.CreationDate)
           WHEN 2 THEN DATEPART("weekday", q.CreationDate)
           WHEN 3 THEN ROUND((CAST(DATEPART("weekday", q.CreationDate) AS numeric) +
                CAST(DATEPART("hour", q.CreationDate) AS numeric) / 24), 2) END
  FROM Posts q
    LEFT OUTER JOIN Posts a ON q.AcceptedAnswerId = a.Id
  WHERE q.AcceptedAnswerId > 0
  )
SELECT Period, AVG(timeDiff)
FROM tmp
-- We cut off answers that arrived more than n minutes after the question to avoid outliers
WHERE timeDiff < @CutOffTime
GROUP BY Period
ORDER BY Period

view current version

edited dec 21 13

created dec 21 13 Anton.