Split date/time ranges into multiple rows - sql

Question

I'm trying to split the date/time ranges in my dataset into multiple rows by hour in SQL Server. My current dataset looks like:
EmployeeCode StartDateTime EndDateTime
843578 2017-05-14 8:30 AM 2017-05-14 3:36 PM
587123 2017-05-14 9:00 AM 2017-05-14 6:28 PM
.....
And my current code seems like it's not catching both Date and Time element in the dataset. I want something like this as my final result.
EmployeeCode StartDateTime EndDateTime
843578 2017-05-14 8:30 AM 2017-05-14 9:00 PM
843578 2017-05-14 9:00 AM 2017-05-14 10:00 AM
843578 2017-05-14 10:00 AM 2017-05-14 11:00 AM
843578 2017-05-14 11:00 AM 2017-05-14 12:00 PM
843578 2017-05-14 12:00 PM 2017-05-14 01:00 PM
843578 2017-05-14 01:00 PM 2017-05-14 02:00 PM
843578 2017-05-14 02:00 PM 2017-05-14 03:00 PM
843578 2017-05-14 03:00 PM 2017-05-14 03:36 PM
587123 2017-05-14 9:00 AM 2017-05-14 10:00 AM
...............
I want to capture both date and time information and expand it to the rows by hour. Also, if an entry starts at 8:30 I want to split it as a separate unit such as 8:30 to 9:00 and the same logic is applied to the end time. (e.g. 3:00 - 3:36) My current code is not complete and I'd appreciate how I should rewrite the code to achieve what I mentioned above.
Select EmployeeCode, StartDateTime, EndDateTime
,StartTime = case when N=datepart(hour,StartDateTime) then StartTime else TimeFromParts(N,0,0,0,0)
end
,EndTime = case when N=datepart(hour,EndDateTime) then EndTime else
TimeFromParts(N+1,0,0,0,0) end
From mytable T
Join ( values (0),(1),(2),(3),(4),(5),(6)
,(7),(8),(9),(10),(11),(12),(13)
,(14),(15),(16),(17),(18),(19),(20)
,(21),(22),(23)
) B(N)
on N between datepart(hour,StartDateTime) and datepart(hour,EndDateTime)

Answer 1

This is a bit messy, but using a few table constructors, you can create a tally and time ranges. Then you use a CASE expression to return the relevant values:
SELECT YT.EmployeeCode,
CASE WHEN YT.StartDateTime > DT.StartDateTime THEN YT.StartDateTime ELSE DT.StartDateTime END AS StartDateTime,
CASE WHEN YT.EndDateTime < DT.EndDateTime THEN YT.EndDateTime ELSE DT.EndDateTime END AS StartDateTime
FROM (VALUES(843578,CONVERT(datetime2(0),'2017-05-14T08:30:00'),CONVERT(datetime2(0),'2017-05-14T15:36:00')),
(587123,CONVERT(datetime2(0),'2017-05-14T09:00:00'),CONVERT(datetime2(0),'2017-05-14T18:28:00')))YT(EmployeeCode,StartDateTime,EndDateTime)
CROSS APPLY (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23))T(I)
CROSS APPLY (VALUES(DATEADD(HOUR,T.I,CONVERT(time(0),'00:00:00')),DATEADD(HOUR,T.I+1,CONVERT(time(0),'00:00:00'))))V(StartTime,EndTime)
CROSS APPLY (VALUES(DATETIMEFROMPARTS(YEAR(YT.StartDateTime),MONTH(YT.StartDateTime),DAY(YT.StartDateTime),DATEPART(HOUR,V.StartTime),DATEPART(MINUTE,V.StartTime),0,0),
DATETIMEFROMPARTS(YEAR(YT.StartDateTime),MONTH(YT.StartDateTime),DAY(YT.StartDateTime),DATEPART(HOUR,V.EndTime),DATEPART(MINUTE,V.EndTime),0,0)))DT(StartDateTime,EndDateTime)
WHERE YT.StartDateTime <= DT.EndDateTime
AND YT.EndDateTime >= DT.StartDateTime;
From the comments, it looks(?) like the OP is using a Procedure to get the data, not a table as alluded to in the question, as they say that they can't use a FROM. You'll need to create a table, and then INSERT that data into it and reference it in the FROM:
CREATE TABLE #t (EmployeeCode int,
StartDatetime datetime2(0),
EndDateTime datetime2(0));
INSERT INTO #t
EXEC dbo.YourProc {Parameters?};
--Then prior solution:
SELECT YT.EmployeeCode,
...
FROM #T YT
CROSS APPLY (VALUES(0),(1)....

Answer 2

Does this do what you need?
Select
EmployeeCode
, final.startDateTime
, final.endDateTime
from
myTable as employee
cross apply ( Select
startDate = convert(date, startDateTime)
, startHour = datepart(hour, startDateTime)
, endDate = convert(date, endDateTime)
, endHour = datepart(hour, endDateTime)
) as times
cross apply (Select
roundedStart = dateadd(hour, startHour, convert(datetime, startDate))
, roundedEnd = dateAdd(hour, endHour + 1, convert(datetime, endDate))
) as rounding
cross apply (Select
[hours] = datediff(hour,roundedStart, roundedEnd)
) as diff
cross apply (Select
increment = ROW_NUMBER() over (order by (select NULL))
from string_split(replicate(' ',diff.[hours] - 1),' ')
) as repeater
cross apply ( Select
startIncrement = dateadd(hour, repeater.increment - 1, roundedStart)
, endInrement = dateadd(hour, repeater.increment, roundedStart)
) as timeIncrements
cross apply (Select
startDateTime = max(startDT)
, endDateTime = min(endDT)
from (values (employee.startDateTime, employee.endDateTime),
(startIncrement, endInrement) ) s (startDT, endDT)
) as final

Answer 3

This seems like a good place to use a recursive CTE:
with cte as (
select employeecode, startdatetime as starthour,
dateadd(hour, datepart(hour, startdatetime) + 1, convert(datetime, convert(date, startdatetime))) as endhour,
enddatetime
from t
union all
select employeecode, endhour,
(case when dateadd(hour, 1, endhour) > enddatetime then enddatetime else dateadd(hour, 1, endhour) end),
enddatetime
from cte
where endhour < enddatetime
)
select *
from cte;
Here is a db<>fiddle.
If you can have more than 100 hours in a period (which seems unlikely because the periods appear to be on the same day), then you need option (maxrecursion 0).