Add "now" row to duration calculation - sql

Question

I have a query that calculates duration of an incident. However, it doesn't include the current time for the still "open" incidents. I am trying to figure out a way to add that to the below. This is running on Azure SQL 12.0.2000.8. Per the example, Incident 18 and 19 are closed (last record has StatusID<>1), so my current calculation is correct. However, Incident 20 is ongoing (last record has StatusId=1) and needs to calculate the time between the last update and now.
Structure:
CREATE TABLE [dbo].[IncidentActions](
[Id] [INT] IDENTITY(1,1) NOT NULL,
[IncidentId] [INT] NOT NULL,
[ActionDate] [DATETIMEOFFSET](7) NOT NULL,
[Description] [NVARCHAR](MAX) NOT NULL,
[StatusId] [INT] NOT NULL
) ON [PRIMARY]
GO
INSERT INTO [dbo].[IncidentActions] VALUES
( 51, 18, N'2020-03-10T13:39:27.8621563+00:00', N'This is a demo of the app ops incident management portal', 1 ),
( 52, 18, N'2020-03-10T13:41:42.4306254+00:00', N'Superfast update we''re on it', 1 ),
( 53, 18, N'2020-03-10T13:42:19.0766735+00:00', N'Found a workaround', 1 ),
( 55, 18, N'2020-03-10T13:44:05.7958553+00:00', N'Suspending for now', 2 ),
( 56, 18, N'2020-03-10T13:44:49.732564+00:00', N'No longer suspended', 1 ),
( 57, 18, N'2020-03-10T13:45:09.8056202+00:00', N'All sorted', 3 ),
( 58, 19, N'2020-03-11T14:47:05.6968653+00:00', N'This is just a test', 1 ),
( 59, 19, N'2020-03-11T14:51:20.4522014+00:00', N'Found workaround and root cause, not yet fixed', 1 ),
( 60, 19, N'2020-03-11T14:52:34.857061+00:00', N'Networking issues, updates suspended', 2 ),
( 61, 19, N'2020-03-11T14:54:48.2262037+00:00', N'Network issue resolved, full functionality restored', 3 ),
( 62, 20, N'2020-03-12T10:49:11.5595048+00:00', N'There is an ongoing issue', 1 ),
( 63, 20, N'2020-03-12T11:29:37.9376805+00:00', N'This incident is ongoing....', 1 )
GO
CREATE TABLE [dbo].[IncidentStatuses](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Description] [nvarchar](500) NOT NULL
) ON [PRIMARY]
GO
INSERT INTO [dbo].[IncidentStatuses] VALUES
( 1, N'OPEN' ), ( 2, N'SUSPENDED' ), ( 3, N'CLOSED' )
GO
Query:
WITH allActions
AS (SELECT IncidentId,
ActionDate,
IncidentStatuses.Description,
ROW_NUMBER() OVER (PARTITION BY IncidentId ORDER BY ActionDate) AS rowNum
FROM IncidentActions
INNER JOIN dbo.IncidentStatuses ON IncidentStatuses.Id = IncidentActions.StatusId
)
,actionPeriods
AS (SELECT firstAction.IncidentId,
firstAction.Description StartStatus,
secondAction.Description EndStatus,
DATEDIFF(SECOND, firstAction.ActionDate, secondAction.ActionDate) SecondsElapsed
FROM allActions firstAction
INNER JOIN allActions secondAction ON firstAction.rowNum +1 = secondAction.rowNum --the next action
AND firstAction.IncidentId = secondAction.IncidentId --for the same incident
)
SELECT
actionPeriods.IncidentId,
SUM(CASE WHEN actionPeriods.StartStatus = 'OPEN' THEN actionPeriods.SecondsElapsed ELSE 0 END) SecondsActive,
SUM(CASE WHEN actionPeriods.StartStatus <> 'OPEN' THEN actionPeriods.SecondsElapsed ELSE 0 END) SecondsInactive,
SUM(actionPeriods.SecondsElapsed) SecondsElapsed
FROM actionPeriods
GROUP BY actionPeriods.IncidentId
GO

Answer 1

Using a CTE is quit overkill. You could use tsql windowing functions. In this case the lag and or lead functions. I have added a sample code based on your tables.
select
IncidentId,
StatusId,actiondate ,
lag(actiondate) over (partition by incidentid order by incidentid, actiondate) as previousrow,
coalesce(
lead(actiondate) over (partition by incidentid order by incidentid, actiondate),
case
when (max(actiondate) over (partition by incidentid order by incidentid) = actiondate) and (statusid = 3) then actiondate
when (max(actiondate) over (partition by incidentid order by incidentid) = actiondate) and (statusid = 1) then convert([DATETIMEOFFSET](7),getdate())
end
) as nextrow
from
dbo.IncidentActions
order by
IncidentId, ActionDate

Answer 2

Applying LEAD instead of a self-join based on Row_number:
WITH allPeriods AS
(
SELECT IncidentId,
Lead(ActionDate) Over (PARTITION BY IncidentId ORDER BY ActionDate DESC) AS ActionDate,
Lead(st.Description) Over (PARTITION BY IncidentId ORDER BY ActionDate DESC) AS StartStatus,
st.Description AS EndStatus,
CASE -- return NOW if the last row is "open"
WHEN Row_Number() Over (PARTITION BY IncidentId ORDER BY ActionDate DESC) = 1
AND StatusId = 1
THEN getdate()
ELSE ActionDate
END AS nextDate
FROM IncidentActions AS act
JOIN dbo.IncidentStatuses AS st
ON st.Id = act.StatusId
),
elapsed AS
( SELECT *,
DATEDIFF(SECOND, ActionDate, nextDate) AS SecondsElapsed
FROM allPeriods
)
SELECT
IncidentId,
Sum(CASE WHEN StartStatus = 'OPEN' THEN SecondsElapsed ELSE 0 END) SecondsActive,
Sum(CASE WHEN StartStatus <> 'OPEN' THEN SecondsElapsed ELSE 0 END) SecondsInactive,
Sum(SecondsElapsed) SecondsElapsed
FROM elapsed
WHERE ActionDate IS NOT NULL
GROUP BY IncidentId
See fiddle

Answer 3

For the curious, the final version, courtesy of Remko
WITH actionPeriods /* This one determines the elapsed time between actions */
AS (SELECT IncidentId,
IncidentStatuses.Description StatusDesc,
/* LAG(ActionDate) OVER (PARTITION BY IncidentId ORDER BY IncidentId, ActionDate) AS previousrow, */
DATEDIFF(SECOND,ActionDate,
COALESCE(LEAD(ActionDate) OVER (PARTITION BY IncidentId ORDER BY IncidentId, ActionDate), /* Lead gets the next action */
CASE /* If the next aciton is NULL, then get either the current time for active, or the original time for closed */
WHEN (MAX(ActionDate) OVER (PARTITION BY IncidentId ORDER BY IncidentId) = ActionDate) AND (StatusId = (SELECT Id FROM dbo.IncidentStatuses WHERE Description = 'CLOSED')) THEN ActionDate
WHEN (MAX(ActionDate) OVER (PARTITION BY IncidentId ORDER BY IncidentId) = ActionDate) AND (StatusId <> (SELECT Id FROM dbo.IncidentStatuses WHERE Description = 'CLOSED')) THEN GETUTCDATE()
END
)
) SecondsElapsed
FROM dbo.IncidentActions
INNER JOIN dbo.IncidentStatuses ON IncidentStatuses.Id = IncidentActions.StatusId
)
SELECT
actionPeriods.IncidentId,
SUM(CASE WHEN actionPeriods.StatusDesc = 'OPEN' THEN actionPeriods.SecondsElapsed ELSE 0 END) SecondsActive, /* This counts periods that are active */
SUM(CASE WHEN actionPeriods.StatusDesc = 'SUSPENDED' THEN actionPeriods.SecondsElapsed ELSE 0 END) SecondsInactive, /* This count periods that are inactive */
SUM(CASE WHEN actionPeriods.StatusDesc IN ('OPEN','SUSPENDED') THEN actionPeriods.SecondsElapsed ELSE 0 END) SecondsElapsed /* We don't want periods that were CLOSED, as the ticket was not elapsing during that time */
FROM actionPeriods
GROUP BY actionPeriods.IncidentId