Split Time Frequency To Rows - sql-server

Question

I am trying to split a time frequency that has a start time, an end time, a frequency and a duration into separate rows. Here is some example data:
+------+------------+----------+-----------------+---------------+
| Name | Start_Time | End_Time | Frequency_Hours | Duration_Mins |
+------+------------+----------+-----------------+---------------+
| A | 08:00:00 | 18:00:00 | 2 | 2 |
| B | 00:00:00 | 23:59:59 | 1 | 5 |
| C | 00:00:00 | 23:59:59 | 4 | 15 |
+------+------------+----------+-----------------+---------------+
Can be created using the following query:
DECLARE #Tmp AS TABLE(Name VARCHAR(128)
,Start_Time VARCHAR(8)
,End_Time VARCHAR(8)
,Frequency_Hours INT
,Duration_Mins INT)
INSERT INTO #Tmp VALUES ('A','08:00:00', '18:00:00', 2,2)
,('B','00:00:00', '23:59:59', 1,5)
,('C','00:00:00', '23:59:59', 4,15)
Here is my desired output (I will then use this to drive a gantt chart visualisation):
+------+------------+----------+
| Name | Start_Time | End_Time |
+------+------------+----------+
| A | 08:00:00 | 08:02:00 |
| A | 10:00:00 | 10:02:00 |
| A | 12:00:00 | 12:02:00 |
| A | 14:00:00 | 14:02:00 |
| A | 16:00:00 | 16:02:00 |
| A | 18:00:00 | 18:02:00 |
| B | 00:00:00 | 00:05:00 |
| B | 01:00:00 | 01:05:00 |
| B | 02:00:00 | 02:05:00 |
| B | 03:00:00 | 03:05:00 |
| B | 04:00:00 | 04:05:00 |
| B | 05:00:00 | 05:05:00 |
| B | 06:00:00 | 06:05:00 |
| B | 07:00:00 | 07:05:00 |
| B | 08:00:00 | 08:05:00 |
| B | 09:00:00 | 09:05:00 |
| B | 10:00:00 | 10:05:00 |
| B | 11:00:00 | 11:05:00 |
| B | 12:00:00 | 12:05:00 |
| B | 13:00:00 | 13:05:00 |
| B | 14:00:00 | 14:05:00 |
| B | 15:00:00 | 15:05:00 |
| B | 16:00:00 | 16:05:00 |
| B | 17:00:00 | 17:05:00 |
| B | 18:00:00 | 18:05:00 |
| B | 19:00:00 | 19:05:00 |
| B | 20:00:00 | 20:05:00 |
| B | 21:00:00 | 21:05:00 |
| B | 22:00:00 | 22:05:00 |
| B | 23:00:00 | 23:05:00 |
| C | 00:00:00 | 00:15:00 |
| C | 04:00:00 | 04:15:00 |
| C | 08:00:00 | 08:15:00 |
| C | 12:00:00 | 12:15:00 |
| C | 16:00:00 | 16:15:00 |
| C | 20:00:00 | 20:15:00 |
+------+------------+----------+
I am hoping to be able to create a view out of this so I am trying to do it without cursors or other cpu intensive methods.
Any ideas?
Thanks,
Dan.

Answer 1

You could use a recursive cte like this
;WITH temp AS
(
SELECT t.Name, CAST(t.Start_Time AS time) AS CurrentStart_Time, dateadd(minute,t.Duration_Mins,CAST(t.Start_Time AS time)) AS CurrentEnd_Time, t.Frequency_Hours, CAST(t.End_Time AS time) AS End_Time
FROM #Tmp t
UNION ALL
SELECT t.Name, dateadd(hour,t.Frequency_Hours,t.CurrentStart_Time), dateadd(hour,t.Frequency_Hours,t.CurrentEnd_Time), t.Frequency_Hours, t.End_Time
FROM temp t
WHERE t.CurrentStart_Time < t.End_Time AND t.CurrentStart_Time < dateadd(hour,t.Frequency_Hours,t.CurrentStart_Time)
)
SELECT t.Name, t.CurrentStart_Time, t.CurrentEnd_Time
FROM temp t
ORDER BY t.Name
OPTION (MAXRECURSION 0)
Demo link: http://rextester.com/XJK25805

Answer 2

It can be done without RECURSIIVE CTE also.
If we create number instead of using
select distinct number master..spt_values then performance will be far better.
Like Number table can be populated from 1 to 100.
try this with various sample data,
declare #t table(Name varchar(20), Start_Time time(0),End_Time time(0)
, Frequency_Hours int,Duration_Mins int)
insert into #t VALUES
('A','08:00:00','18:00:00', 2 , 2 )
,('B','00:00:00','23:59:59', 1 , 5 )
,('C','00:00:00','23:59:59', 4 ,15 )
SELECT NAME
,dateadd(hour, n, Start_Time) Start_Time
,dateadd(minute, Duration_Mins, (dateadd(hour, n, Start_Time))) End_Time
FROM #t t
CROSS APPLY (
SELECT DISTINCT number * Frequency_Hours n
FROM master..spt_values
WHERE number >= 0
AND number <= datediff(HOUR, t.Start_Time, t.End_Time) / Frequency_Hours
) ca