SQL calculate DayTime and NightTime between two DateTime values - sql

Question

I am way over my head with an SQL problem. I have a query which makes a temporary table, fills it with data from several other tables, makes some calculations and updates and provides this data to an app. The final step to do is calculate how many hours and how many minutes there are between two datetimes, but they should be divided in dayHours, dayMins, nightHours, nightMins (datetimes can be 20+ days in between). The following bulletpoints will visualize what I want to do:
Let say, night time is from 23:00 to 06:00.
We have DateTime1 = 20-04-2016 13:30.
We have DateTime2 = 21-04-2016 07:15.
NightTime: from 23:00 to 06:00 = 7 hours 0 minutes.
DayTime: from 13:30 to 23:00 (9h30m), and then again from 06:00 to 07:15(1h15m) the following day for a total of 10 hours 45 minutes.
I am providing a create table query, but I only need help with the calculation so you could ignore my table and data. Note, I have erased almost all formatting to reduce, as the post got really long.
CREATE TABLE [dbo].[myTestTable](
[JHID] [int] NULL, [ToDateTime] [datetime] NULL,
[startPayDateTime] [datetime] NULL, [opDayHour] [int] NULL,
[opDayMin] [int] NULL, [opNightHour] [int] NULL,
[opNightMin] [int] NULL, ) ON [PRIMARY] GO
Consider inserting this as a test data. The columns (for test purposes) are startPayDateTime and ToDateTime
INSERT INTO [myTestTable]
([JHID],[ToDateTime],[startPayDateTime],[opDayHour],[opDayMin],[opNightHour],[opNightMin])
VALUES (301533,'14-03-2016 01:54','14-03-2016 04:54',1,1,1,1),
(302488,'14-03-2016 01:54','14-03-2016 08:31',0,0,0,0),
(302676,'14-03-2016 01:54','28-03-2016 08:11',1,1,1,1) GO
So now I have to
UPDATE
SET opDayHour = (CASE WHEN ... THEN *value* ELSE 0 end),
opDayMin = (CASE WHEN ... THEN *value* ELSE 0 end),
opNightHour = (CASE WHEN ... THEN *value* ELSE 0 end),
opNightMin = (CASE WHEN ... THEN *value* ELSE 0 end),
How do I Thank you for your consideration, if my question is not clear enough leave a comment ! :)

Answer 1

The idea is to detect first day, a number of hole days (if present) and the last day (if not the same as first). So we need only one day long tally table for minutes. Drawback is more computations of those first/last intervals. When you need computations wich involve a number of intermidiate variables CROSS APPLY is a handy tool.
Try this, you may need to ajust +-1 logic to conform to your rules. This query computes minutes which can be easily converted to hours + minutes.
with myMinutes as (
select rn
-- day time is from 6:00 to 23:00
, mday = case when rn between 6*60 and 23*60-1 then 1 else 0 end
, mnight = 1 - case when rn between 6*60 and 23*60-1 then 1 else 0 end
from (select top(24*60) rn=row_number () over (order by (select null))
from sys.all_objects s1, sys.all_objects s2) t
)
select dayMinutes=r1.dayMin + case holedays when 0 then 0 else r2.dayMin + (holedays-1)*(23*60 - 6*60) end
, nightMinutes=r1.nightMin + case holedays when 0 then 0 else r2.nightMin + (holedays-1)*(24*60 -(23*60 - 6*60)) end
, totalMinutes= datediff(MINUTE, [FromDateTime], [ToDateTime]) -- control
,[JHID],[JetReg],[ArrFltID],[DepFltID],[ArrDateTime],[FromDateTime],[ToDateTime]
-- more columns sipped
from [myTestTable]
cross apply (select fD = dateadd(DAY,datediff(DAY,'19000101',[FromDateTime]),'19000101')
,tD = dateadd(DAY,datediff(DAY,'19000101',[ToDateTime]),'19000101')
,holedays = datediff(DAY,[FromDateTime],[ToDateTime]) ) xd
cross apply (select fFirstMin = datediff(MINUTE, fd, [FromDateTime])
,fLastMin = case holedays when 0 then datediff(MINUTE, td,[ToDateTime]) else 24*60 end - 1
,tFirstMin = 1
,tLastMin = datediff(MINUTE, td, [ToDateTime])
) xb
cross apply (select dayMin = sum(mm.mday)
, nightMin = sum(mm.mnight)
from myminutes mm
where mm.rn between fFirstMin and fLastMin ) r1
cross apply (select dayMin = sum(mm.mday)
, nightMin = sum(mm.mnight)
from myminutes mm
where mm.rn between tFirstMin and tLastMin ) r2

Answer 2

You can use cte for that count:
DECLARE
#DateTime1 datetime = '2016-04-20 13:30',
#DateTime2 datetime = '2016-04-21 07:15'
;WITH times AS(
SELECT #DateTime1 as d,
CASE WHEN DATEPART(hour,#DateTime1) between 6 and 22 then 'd' else 'n' end as a,
0 as m
UNION ALL
SELECT DATEADD(minute,1,d),
CASE WHEN DATEPART(hour,DATEADD(minute,1,d)) between 6 and 22 then 'd' else 'n' end as a,
DATEDIFF(minute,d,DATEADD(minute,1,d))
FROM times
WHERE DATEADD(minute,1,d) <= #DateTime2
)
SELECT CASE WHEN a = 'd' THEN 'DayTime' ELSE 'NightTime' END as TimePart,
sum(m)/60 as H,
sum(m) - (sum(m)/60)* 60 as M
FROM times
GROUP BY a
OPTION (MAXRECURSION 0)
Output be like:
TimePart H M
--------- ----------- -----------
DayTime 10 45
NightTime 7 0
(2 row(s) affected)