Group by Time Interval

Question

I need to Group my Table into 15 minutes Intervals. I can do that with:

select dateadd(minute, datediff(minute, 0, ts) / 15 * 15, 0), sum (goodpieces) 
from Stat         


        

Answer 1

Something like this might help you.

declare @startDate datetime
        ,@endDate datetime

set @startDate = '2011-10-25'
set @endDate = '2011-10-26'

;with fifteenMinutes
as
(
    select  dateadd(minute, datediff(minute, 0, @startDate) / 15 * 15, 0) as q
    UNION ALL
    select  dateadd(minute, 15, q)
    from fifteenMinutes
    where q < @endDate
)

select * from fifteenMinutes

Answer 2

Create a table with every possible timestamp in 15 minute increments, and do a LEFT JOIN from it to your query above.

SELECT * FROM timestamps LEFT JOIN (SELECT dateadd......) ON timestamps.timestamp = StationCount.ts

If you know your chart always covers a 24 hour period, you only need to create a table with the numbers 0-95, then for each entry add it to the start time of your chart.

SELECT *
  FROM (SELECT dateadd(minute, <starttime>, number*15) timestamp FROM numbers) timestamps LEFT JOIN
       (SELECT dateadd......) ON timestamps.timestamp = StationCount.ts