Determine time duration based on events without using loops - sql

Question

I have a table with timestamps of 5 different types of events (start, stopped, restart, aborted, and completed).
The given table looks like this:
Time
EventID
Event
7:38:20
1
start
7:40:20
2
stopped
7:48:20
3
restart
7:50:20
4
aborted
8:00:20
1
start
8:40:20
5
completed
8:58:20
1
start
9:00:15
4
aborted
I would like to determine the following and display it:
Duration of individual Wash --> From (start or restart) to (stopped or aborted or completed)
Duration of Wash Cycle --> From (start) to (aborted or completed)
Duration of total wash time --> Sum of all individual wash in a Wash cycle
Duration of idle time --> Wash Cycle duration - total wash time duration
So the table should look something like the following:
Time
EventID
Event
Duration of individual Wash
Duration of Wash Cycle
Duration of total wash time
Duration of idle time
7:38:20
1
start
0:02:00
0:12:00
0:04:00
0:08:00
7:40:20
2
stopped
NULL
NULL
NULL
NULL
7:48:20
3
restart
0:02:00
NULL
NULL
NULL
7:50:20
4
aborted
NULL
NULL
NULL
NULL
8:00:20
1
start
0:40:00
0:40:00
0:01:55
0:00:00
8:40:20
5
completed
NULL
NULL
NULL
NULL
8:58:20
1
start
0:01:55
0:01:55
0:01:55
0:00:00
9:00:15
4
aborted
NULL
NULL
NULL
NULL
So far I was able to get the duration of individual Wash and the duration of Wash Cycle by joining two table (one with only start, abort, and complete; the other with all events). I am stuck on the last two columns. I'm not sure how to approach this problem efficiently without using a while loop or counter of some sort. Would love some pointers.
Here are my code so far:
SELECT IndivWash.DateTimeStamp as 'Event TimeStamp'
,IndivWash.EventIDNo AS 'Event ID Number'
,IndivWash.EventDesc AS 'Event Description'
-- for the duration of the WASH ----------------------------------------------------
,CASE
WHEN (IndivWash.EventIDNo = '1' OR IndivWash.EventIDNo = '3')
AND (LEAD(IndivWash.EventIDNo) OVER (ORDER BY IndivWash.DateTimeStamp) = '2'
OR LEAD(IndivWash.EventIDNo) OVER (ORDER BY IndivWash.DateTimeStamp) = '4'
OR LEAD(IndivWash.EventIDNo) OVER (ORDER BY IndivWash.DateTimeStamp) = '5')
AND LEAD(IndivWash.EventIDNo) OVER (ORDER BY IndivWash.DateTimeStamp) <> IndivWash.EventIDNo
THEN
DATEDIFF(s, IndivWash.DateTimeStamp, LEAD(IndivWash.DateTimeStamp) OVER (ORDER BY IndivWash.DateTimeStamp))
ELSE
NULL
END AS 'Duration of individual Wash'
-- For the duration of the CYCLE ----------------------------------------------------
,CASE
WHEN WashCycle.EventIDNo = '1'
AND LEAD(WashCycle.EventIDNo) OVER (ORDER BY WashCycle.DateTimeStamp) <> WashCycle.EventIDNo
AND (LEAD(WashCycle.EventIDNo) OVER (ORDER BY WashCycle.DateTimeStamp) = '4' OR
LEAD(WashCycle.EventIDNo) OVER (ORDER BY WashCycle.DateTimeStamp) = '5')
THEN
DATEDIFF(s, WashCycle.DateTimeStamp, LEAD(WashCycle.DateTimeStamp) OVER (ORDER BY WashCycle.DateTimeStamp))
ELSE
NULL
END AS 'Duration of Wash Cycle'
-- ----------------------------------------------------
FROM (
--FROM: table with only start, abort and complete.
-- to differentiate the cycles that are not aborted
SELECT TOP (1000) DateTimeStamp
,EventIDNo
,EventDesc
/*----------CHANGE DATABASE HERE----------*/
FROM Washer.dbo.EventLog_vw
/*----------------------------------------*/
WHERE EventIDNo IN ('1','4','5')
ORDER BY DateTimeStamp
) WashCycle
RIGHT JOIN
(
--FROM: table with all five events
SELECT TOP (1000)
DateTimeStamp
,EventIDNo
,EventDesc
/*----------CHANGE DATABASE HERE----------*/
FROM Washer.dbo.EventLog_vw
/*----------------------------------------*/
WHERE EventIDNo IN ('1','2','3','4','5')
ORDER BY DateTimeStamp
) IndivWash
ON WashCycle.DateTimeStamp=IndivWash.DateTimeStamp

Answer 1

Try this example based on precalculating cycles IDs CycleStartId and CycleRestartId:
SELECT *,
CASE WHEN EventID IN (1, 3) THEN
DATEDIFF(SS,
MIN(Time) OVER (PARTITION BY CycleRestartId),
MAX(Time) OVER (PARTITION BY CycleRestartId)
)
END AS DurIndSec,
CASE WHEN EventID IN (1) THEN
DATEDIFF(SS,
MIN(Time) OVER (PARTITION BY CycleStartId),
MAX(Time) OVER (PARTITION BY CycleStartId)
)
END AS DurSec,
CASE WHEN EventId = 1 THEN
SUM(CASE WHEN EventId = 1 THEN 0 ELSE TimeDiff END) OVER (PARTITION BY CycleStartId)
END AS TotalWashSec,
CASE WHEN EventId = 1 THEN
SUM(COALESCE(StopIdle, 0)) OVER (PARTITION BY CycleStartId)
END AS DurIdleSec
FROM (
SELECT *,
DATEDIFF(SS, LAG(Time, 1, Time) OVER (ORDER BY Time), Time) as TimeDiff,
SUM(CASE WHEN EventID = 1 THEN 1 ELSE 0 END)
OVER (ORDER BY Time) AS CycleStartId,
SUM(CASE WHEN EventID IN (1, 3) THEN 1 ELSE 0 END)
OVER (ORDER BY Time) AS CycleRestartId,
CASE WHEN LAG(EventId, 1, EventId) OVER (ORDER BY Time) = 2 THEN
DATEDIFF(SS, LAG(Time, 1, Time) OVER (ORDER BY Time), Time)
END AS StopIdle
FROM events
) t
Here the reports are shown in seconds. If you need to format them as time, then you can use the following expression:
CONVERT(varchar(8), DATEADD(SS, <Int in seconds>, '0:00:00'), 114)
fiddle