Getting Minutes by Hour for Date Range - sql

Question

I'm trying to write a SQL query (SQL Server) and part of it is determining the number of minutes per hour between two datetimes.
Example: 11/1/2018 09:05 - 11/1/2018 13:15
Hour 09: 55 minutes
Hour 10: 60 minutes
Hour 11: 60 minutes
Hour 12: 60 minutes
Hour 13: 15 minutes
These would then get put into a temp table and grouped by some other data which will then be used to calculate dollar amounts from these minutes.
Is there a way to accomplish something like this via SQL that isn't too slow or laborious?
Thanks!

Answer 1

I think a recursive CTE is possibly the best approach:
with cte as (
select startTime, endTime,
startTime_hour as hourStart,
(case when endTime < dateadd(hour, 1, startTime_hour) then endTime
else dateadd(hour, 1, startTime_hour)
end) as hourEnd
from (select t.*,
dateadd(hour, datediff(hour, 0, startTime), 0) as startTime_hour
from t
) t
union all
select startTime, endTime,
dateadd(hour, 1, hourStart) as hourStart,
(case when endTime < dateadd(hour, 2, hourStart) then endTime
else dateadd(hour, 2, hourStart)
end) as endHour
from cte
where hourEnd < endTime
)
select cte.hourStart,
(case when hourStart > startTime then datediff(minute, hourStart, hourEnd) else datediff(minute, startTime, hourEnd) end) as minutes
from cte
order by hourStart;
Here is a db<>fiddle.

Answer 2

Here is an alternative dynamic solution that you can work with two parameters (start/end dates) only:
create table #temp
([hour] int, [minutes] int)
declare #startTime datetime='11/1/2018 09:05'
declare #EndTime datetime='11/1/2018 13:15'
declare #tempStartTime datetime = #startTime
declare #nextTimeRounded datetime
declare #hourdiff int = DATEDIFF(HOUR,#startTime,#EndTime)
declare #counter int = DATEPART(HH,#startTime)
declare #limit int = #counter + #hourdiff + 1
while #counter < #limit
begin
insert into #temp ([hour]) values (#counter)
set #nextTimeRounded= (dateadd(hour,
1 + datepart(hour, #tempStartTime),
cast(convert(varchar(10),#tempStartTime, 112) as datetime))
)
if #nextTimeRounded > #EndTime
begin
set #nextTimeRounded = #EndTime
end
update #temp
set [minutes] = (case when DATEDIFF(MINUTE,#tempStartTime,#nextTimeRounded)=0 then 60 else DATEDIFF(MINUTE,#tempStartTime,#nextTimeRounded) end)
where [hour] = #counter
set #counter = #counter + 1
set #tempStartTime = DATEADD(MINUTE,DATEDIFF(MINUTE,#tempStartTime,#nextTimeRounded),#tempStartTime);
end
select * from #temp

Answer 3

Sample Data
Below, we pump four time ranges, with associated values, into a table. All time ranges are different, but the first two are 10h 30m apart. The second two are 9h 45m apart.
declare #times table (
startTime time,
endTime time,
val float
);
insert #times values
('2018-10-01 01:00:00', '2018-10-01 10:45:00', 7),
('2018-10-02 01:00:00', '2018-10-02 10:45:00', 8),
('2018-10-01 01:00:00', '2018-10-01 11:30:00', 1),
('2018-10-02 01:00:00', '2018-10-02 11:30:00', 3);
Solution
You can use the 'datediff' function to aggregate as you so desire. Use the modulo operator to convert your minutes into just the minutes that remain over when whole hours are discounted.
select ap.h,
ap.m,
sumVal = sum(val)
from #times
cross apply (select
h = datediff(hour, startTime, endTime),
m = datediff(minute, startTime, endTime) % 60
) ap
group by ap.h,
ap.m