Get list with start and end values from table of datetimes

Question

Currently i have a table built up like this way

DeviceID      Timestamp            Value
----------------------------------------
Device1       1.1.2011 10:0         


        

Answer 1

The basic idea for the below solution has been borrowed from this answer.

WITH data (DeviceID, Timestamp, Value) AS (
  SELECT 'Device1', CAST('1.1.2011 10:00:00' AS datetime), 3 UNION ALL
  SELECT 'Device1',      '1.1.2011 10:00:01',              4 UNION ALL
  SELECT 'Device1',      '1.1.2011 10:00:02',              4 UNION ALL
  SELECT 'Device1',      '1.1.2011 10:00:04',              3 UNION ALL
  SELECT 'Device1',      '1.1.2011 10:00:05',              4 UNION ALL
  SELECT 'Device1',      '1.1.2011 14:23:14',              8 UNION ALL
  SELECT 'Device1',      '1.1.2011 14:23:15',              7 UNION ALL
  SELECT 'Device1',      '1.1.2011 14:23:17',              4 UNION ALL
  SELECT 'Device1',      '1.1.2011 14:23:18',              2
),
ranked AS (
  SELECT
    *,
    rn = ROW_NUMBER() OVER (PARTITION BY DeviceID ORDER BY Timestamp)
  FROM data
),
starts AS (
  SELECT
    r1.DeviceID,
    r1.Timestamp,
    rank = ROW_NUMBER() OVER (PARTITION BY r1.DeviceID ORDER BY r1.Timestamp)
  FROM ranked r1
    LEFT JOIN ranked r2 ON r1.DeviceID = r2.DeviceID
      AND r1.rn = r2.rn + 1
      AND r1.Timestamp <= DATEADD(second, 5, r2.Timestamp)
  WHERE r2.DeviceID IS NULL
),
ends AS (
  SELECT
    r1.DeviceID,
    r1.Timestamp,
    rank = ROW_NUMBER() OVER (PARTITION BY r1.DeviceID ORDER BY r1.Timestamp)
  FROM ranked r1
    LEFT JOIN ranked r2 ON r1.DeviceID = r2.DeviceID
      AND r1.rn = r2.rn - 1
      AND r1.Timestamp >= DATEADD(second, -5, r2.Timestamp)
  WHERE r2.DeviceID IS NULL
)
SELECT
  s.DeviceID,
  Started = s.Timestamp,
  Ended = e.Timestamp
FROM starts s
  INNER JOIN ends e ON s.DeviceID = e.DeviceID AND s.rank = e.rank