T-SQL - DateTime Gap Distribution - sql-server

Question

Code:
DECLARE #SD DATE = '2017-01-01'
,#ED DATE = '2017-01-07'
,#ST TIME = '08:00:00'
,#ET TIME = '16:00:00';
DECLARE #DT_T TABLE (SDT DATETIME, EDT DATETIME)
Goal:
To combine Start/End Date and Start/End Time (#SD/#ED and #ST/#ET) and create a table with gap intervals between StartDateTime and EndDateTime as shown in the desired output below.
Desired Output
/* #DT_T Data
SDT EDT
2017-01-01 08:00:00 2017-01-01 16:00:00
2017-01-02 08:00:00 2017-01-02 16:00:00
2017-01-03 08:00:00 2017-01-03 16:00:00
2017-01-04 08:00:00 2017-01-04 16:00:00
2017-01-05 08:00:00 2017-01-05 16:00:00
2017-01-06 08:00:00 2017-01-06 16:00:00
2017-01-07 08:00:00 2017-01-07 16:00:00
*/
I'm trying with the numbers table but so far not getting anywhere close.

Answer 1

Something like this? rextester: http://rextester.com/ULTV27021
declare #sd date = '2017-01-01'
,#ed date = '2017-01-07'
,#st_hour int = 8
,#et_hour int = 16;
declare #dt_t table (sdt datetime, edt datetime);
;with n as (select n from (values(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) t(n))
, d as (
select
sdt=dateadd(hour,#st_hour,convert(datetime,dateadd(day, row_number() over (order by (select 1)) -1,#sd)))
, edt=dateadd(hour,#et_hour,convert(datetime,dateadd(day, row_number() over (order by (select 1)) -1,#sd)))
from n as deka
cross join n as hecto
cross join n as kilo /* 2.73 years */
--cross join n as [10k] /* 27.3 years */
)
insert into #dt_t (sdt,edt)
select top (datediff(day,#sd,#ed)+1)
sdt
, edt
from d
order by sdt;
select * from #dt_t
note: rextester's default output formatting for dates is dd.MM.yyyy

Answer 2

Try this. Should get what you want.
DECLARE #SD DATE = '2017-01-01'
,#ED DATE = '2017-01-07'
,#ST TIME = '08:00:00'
,#ET TIME = '16:00:00';
DECLARE #DT_T TABLE (SDT DATETIME, EDT DATETIME)
Declare #i int = 0
While (#SD < #ED)
Begin
Insert Into #DT_T(SDT, EDT)
Select Cast(Convert(varchar(10),DateAdd(Day,#i,#SD),21) + ' ' + Convert(varchar(8),#ST,21) as datetime), Cast(Convert(varchar(10),DateAdd(Day,#i,#SD),21) + ' ' + Convert(varchar(10),#ET,21) as DateTime)
Set #i = #i + 1
IF (DateAdd(Day,#i,#SD) = #ED)
Break
Else
Continue
END
Insert Into #DT_T(SDT, EDT)
Select Cast(Convert(varchar(10),#ED,21) + ' ' + Convert(varchar(8),#ST,21) as datetime), Cast(Convert(varchar(10),#ED,21) + ' ' + Convert(varchar(10),#ET,21) as DateTime)
Select SDT, EDT From #DT_T

Answer 3

Use the next approach
use datediff function for inserting the rows between the 2
ranges.
update only the time in datetime values.
Demo:-
DECLARE #SD DATE = '2017-01-01'
,#ED DATE = '2017-01-07'
,#ST TIME = '08:00:00'
,#ET TIME = '16:00:00';
DECLARE #DT_T TABLE (SDT DATETIME, EDT DATETIME)
DECLARE #start int
set #start = 0
while #start <= datediff(day,#SD,#ED)
begin
insert into #DT_T values
( dateadd(day,#start, #SD) ,
dateadd(day,#start, #SD))
set #start = #start + 1
end
UPDATE #DT_T
SET SDT = DATEADD(HOUR, 8, CAST(CAST(SDT AS DATE) AS DATETIME)) ,
EDT = DATEADD(HOUR, 16, CAST(CAST(EDT AS DATE) AS DATETIME))
select * from #DT_T
Result:-

Answer 4

I'll often use a TVF to create dynamic date/time ranges. A tally table would do the trick as well. The UDF can be faster than a recursive CTE and is parameter driven. You supply the date range, DatePart and Increment. For Example:
Declare #D1 datetime = '2017-01-01'
Declare #D2 datetime = '2017-01-07'
Declare #T1 datetime = '08:00'
Select RetSeq
,STD = RetVal
,EDT = DateAdd(HOUR,8,RetVal)
From [dbo].[udf-Range-Date](#D1+#T1,#D2+#T1,'DD',1)
Returns
The UDF if needed
CREATE FUNCTION [dbo].[udf-Range-Date] (#R1 datetime,#R2 datetime,#Part varchar(10),#Incr int)
Returns Table
Return (
with cte0(M) As (Select 1+Case #Part When 'YY' then DateDiff(YY,#R1,#R2)/#Incr When 'QQ' then DateDiff(QQ,#R1,#R2)/#Incr When 'MM' then DateDiff(MM,#R1,#R2)/#Incr When 'WK' then DateDiff(WK,#R1,#R2)/#Incr When 'DD' then DateDiff(DD,#R1,#R2)/#Incr When 'HH' then DateDiff(HH,#R1,#R2)/#Incr When 'MI' then DateDiff(MI,#R1,#R2)/#Incr When 'SS' then DateDiff(SS,#R1,#R2)/#Incr End),
cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
cte2(N) As (Select Top (Select M from cte0) Row_Number() over (Order By (Select NULL)) From cte1 a, cte1 b, cte1 c, cte1 d, cte1 e, cte1 f, cte1 g, cte1 h ),
cte3(N,D) As (Select 0,#R1 Union All Select N,Case #Part When 'YY' then DateAdd(YY, N*#Incr, #R1) When 'QQ' then DateAdd(QQ, N*#Incr, #R1) When 'MM' then DateAdd(MM, N*#Incr, #R1) When 'WK' then DateAdd(WK, N*#Incr, #R1) When 'DD' then DateAdd(DD, N*#Incr, #R1) When 'HH' then DateAdd(HH, N*#Incr, #R1) When 'MI' then DateAdd(MI, N*#Incr, #R1) When 'SS' then DateAdd(SS, N*#Incr, #R1) End From cte2 )
Select RetSeq = N+1
,RetVal = D
From cte3,cte0
Where D<=#R2
)
/*
Max 100 million observations -- Date Parts YY QQ MM WK DD HH MI SS
Syntax:
Select * from [dbo].[udf-Range-Date]('2016-10-01','2020-10-01','YY',1)
Select * from [dbo].[udf-Range-Date]('2016-01-01','2017-01-01','MM',1)
*/