Average per quarter hour - sql

Question

I have a table with these columns:
Id, Method, DateTime, time taken
Ex
1, Done, 2014-06-22 08:18:00.000, 2000
2, Not Done, 2014-06-23 04:15:00.000, 5000
3, Done, 2014-06-23 14:15:00.000, 6000
I want to have a result set as, "average time taken by DONE methods in each 15 min interval between 8AM to 15PM"
Please guide me on how to proceed on this, I am not sure if cursor fits in this req.

Answer 1

You can use a CTE to generate a list of quarters. Then left join to look up the run times per quarter. A group by will allow you to calculate the average.
In SQL Server 2012, the time type is available, and you can:
; with quarters as
(
select cast('08:00' as time) as time
union all
select dateadd(minute, 15, time)
from quarters
where time <= '14:30'
)
select q.time
, avg(rt.time_taken) as avg_time_taken
from quarters q
left join
RunTime rt
on q.time <= cast(rt.dt as time)
and cast(rt.dt as time) < dateadd(minute, 15, q.time)
and method = 'Done'
group by
q.time
Live example at SQL Fiddle.
For SQL Server 2008R2 and earler, you can use integer math instead:
; with quarters as
(
select 8*60 as min
union all
select min + 15
from quarters
where min < 15*60
)
select q.min / 60 as hour
, q.min % 60 as minute
, avg(rt.time_taken) as avg_time_taken
from quarters q
left join
(
select datepart(minute, dt) +
60 * datepart(hour, dt) as min
, time_taken
from RunTime
where method = 'Done'
) rt
on q.min <= rt.min and rt.min < q.min + 15
group by
q.min;
Live example at SQL Fiddle.

Answer 2

I'm not entirely sure if this is what you want, but here ist the code:
CREATE TABLE #Test(
id int IDENTITY(1,1) PRIMARY KEY,
Method nvarchar(50),
[Datetime] datetime,
timeTaken Bigint
)
CREATE TABLE #Result(
[Between] datetime,
[And] datetime,
[Avg] bigint)
INSERT INTO #Test (Method,Datetime,timeTaken)
VALUES(
'Done', '2014-06-22 08:18:00.000', 2000),
('Not Done', '2014-06-23 04:15:00.000', 5000),
('Done', '2014-06-23 14:15:00.000', 6000)
DECLARE #MaxTime datetime,#StartTime datetime,#Next datetime
SELECT #MaxTime = MAX([datetime]),
#StartTime = MIN([datetime])
FROM #TEST
WHILE #StartTime <= #MaxTime
BEGIN
SET #Next = (SELECT Dateadd(MINUTE,15,#StartTime))
INSERT INTO #Result
SELECT #StartTime AS [Between], #Next AS [And],AVG(timeTaken) AS [AVG]
FROM #Test
WHERE [Datetime] Between #StartTime AND #Next
AND Method = 'Done'
SET #StartTime = #Next
END
SELECT * FROM #Result
DROP TABLE #Test
DROP TABLE #Result
You can now set a where to the Select * from #result in which you can say between 8 AM and 3 PM
Please let me know if this is what you want
Etienne