Vous pouvez le faire facilement en pivoting les données. Cela peut être fait de deux manières.
1.Utilisez Conditional Aggregate pour faire pivoter les données. Après pivoting vous pouvez trouver datediff entre les différentes étapes. Essayez ceci.
SELECT orderid,Received,Keyed,Printed,Delivered,
Datediff(minute, Received, Keyed) TurnTime1,
Datediff(minute, Keyed, Printed) TurnTime2,
Datediff(minute, Printed, Delivered) TurnTime3
FROM (SELECT OrderID,
Max(CASE WHEN ActivityID = 1 THEN ActivityDate END) Received,
Max(CASE WHEN ActivityID = 2 THEN ActivityDate END) Keyed,
Max(CASE WHEN ActivityID = 3 THEN ActivityDate END) Printed,
Max(CASE WHEN ActivityID = 4 THEN ActivityDate END) Delivered
FROM Yourtable
GROUP BY OrderID)A
2.utilisez Pivot transposer les données
SELECT orderid,
[1] AS Received,
[2] AS Keyed,
[3] AS Printed,
[4] AS Delivered,
Datediff(minute, [1], [2]) TurnTime1,
Datediff(minute, [2], [3]) TurnTime2,
Datediff(minute, [3], [4]) TurnTime3
FROM Yourtable
PIVOT (Max(ActivityDate)
FOR ActivityID IN([1],[2],[3],[4]))piv