SELECT t1.FileName, t1.CreatedDate, t2.CreatedDate as PrevCreatedDate
FROM
(SELECT FileName, CreateDate,
ROW_NUMBER() OVER(PARTITION BY FileName ORDER BY CreatedDate) AS OrderNo
FROM MyTable) t1
LEFT JOIN
(SELECT FileName, CreateDate,
ROW_NUMBER() OVER(PARTITION BY FileName ORDER BY CreatedDate) AS OrderNo
FROM MyTable) t2
ON (t1.FileName = t2.FileName AND t1.OrderNo = t2.OrderNo - 1)
Ou pode ser melhor usar 'COM', porque as consultas são idênticas:
WITH t(ObjectID, FileName, CreatedDate, OrderNo) AS
(SELECT ObjectID, FileName, CreatedDate,
ROW_NUMBER() OVER(PARTITION BY FileName ORDER BY CreatedDate) AS OrderNo
FROM MyTable)
SELECT t1.ObjectID, t1.FileName, t1.CreatedDate, t2.CreatedDate AS PrevCreatedDate,
DATEDIFF("SS", '1900-01-01 00:00:00',
COALESCE((t1.CreatedDate - t2.CreatedDate),0)) AS secondsTaken
FROM t t1 LEFT JOIN t t2
ON (t1.FileName = t2.FileName AND t1.OrderNo = t2.OrderNo + 1)
