Re: Aggregates: Largest Groups

From: Daniel Pitts <>
Date: Mon, 22 Mar 2010 15:54:39 -0700
Message-ID: <PySpn.105142$1n5.38222_at_newsfe04.iad>

On 3/22/2010 2:48 PM, David Fetter wrote:
> Gene Wirchenko<>  wrote:

>> On Mon, 22 Mar 2010 16:12:50 -0500, (David Fetter)
>> wrote:
>>> Gene Wirchenko<> wrote:
>>>> On Mon, 22 Mar 2010 15:42:09 -0500, (David Fetter)
>>>> wrote:
>>>>> Let's say I have a traffic monitoring system. The stream of data
>>>>> coming in records a timestamp and a speed for each vehicle.
>>>>> I'd like to know what all the groups of vehicles larger than X whose
>>>>> with average speed over Y is.
>>>>> Any ideas how to approach this?
>>>> First, define your terms. What is a group? What does "larger
>>>> than X" mean? (Size of vehicle? Number of vehicles in the group?)
>>> Number of vehicles in the group.
>> And what is a group?

> Those vehicles, grouped in time, whose average speed is>= Y. How are you grouping them in time?
That seems to be the missing detail.

If you are grouping them in time already, then you have your answer, just calculate the X and Y for that group, and filter out the ones that don't match. Received on Mon Mar 22 2010 - 17:54:39 CDT

Original text of this message