Thanks folks for the ideas. Between them and some time "sawing logs" I
have a found a solution using a UDF that does math on the DateTime value.
Here is demo code:
m.TSref = DATETIME()
CREATE CURSOR joe (Stamp T, Value n(4))
FOR nn = 1 TO 100000
INSERT INTO joe VALUES (m.TSref + nn, 1000*RAND())
NEXT
SELECT Period(Stamp) as Period, Stamp, AVG(Value) as Joe;
FROM joe;
GROUP BY 1;
INTO CURSOR Out
FUNCTION Period
PARAMETERS m.ts
RETURN INT((m.Ts - m.TSref) / 60) && 60 = 1 per minute, 3600 = 1 per hour
etc
Now that I have the grouping issue solved I need to combine multiple
selects into one cursor. I'll start another thread unless I find the
answer right away.
Thanks again,
Joe
On Mon, Jun 9, 2014 at 9:47 AM, Tracy Pearson <[email protected]> wrote:
> Joe Yoder wrote on 2014-06-08:
> > Scenario:
> > - Cursor with 2 fields TimeStamp T, and Value N(4.0) - 1 record per
> > second - Output needed - BegStamp as the beginning of a time period
> > X seconds long and Avg as the average of the Value field for X
> > seconds
> > With X = 3600 the results should give the average value for each hour.
> >
> > I'm stuck on what to use for a group by expression and suspect that the
> > best way may be to hard code a pair of loops that increments through the
> > cursor one time period at a time.
> >
> > Does anyone want to show me a better way?
> >
> > Thanks in advance,
> >
> > Joe
> >
>
> Joe,
>
> I would accomplish this using a subquery.
>
> CREATE CURSOR joe (TimeStamp T, Value n(4))
> FOR nn = 1 TO 10000
> INSERT INTO joe VALUES (DATETIME() + nn, 1000*RAND())
> NEXT
>
> startTime = DATETIME() + 1234
> endTime = startTime + 3600 - 1 && fencepost
>
> SELECT grouping, AVG(value) ;
> FROM (SELECT value, 1 as grouping ;
> FROM joe ;
> WHERE TimeStamp between startTime AND endTime) ;
> average GROUP BY 1
>
>
> Tracy Pearson
> PowerChurch Software
>
>
[excessive quoting removed by server]
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