Re: Flatten table using timestamp and source

HI Raj

If source changes, in this case from 1 to 2, then etime would be the last
value of stime for source =1; So for source 1 it starts at stime 13:00 and
continues till 13:02 (etime).

This should result in 3 records, because source is 1, then 2, then 1 again.
I hope this explains ?

-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org [mailto:pgsql-sql-owner(at)postgresql(dot)org]
On Behalf Of Raj Mathur (??? ?????)
Sent: 24 May 2012 01:59 PM
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] Flatten table using timestamp and source

On Thursday 24 May 2012, Elrich Marx wrote:
> I am quite new to Postgres, so please bear with me.
>
> I have a table with data in the following format:
>
> Table name : Time_Source_Table
>
> Source , Stime
> 1, "2012-05-24 13:00:00"
> 1, "2012-05-24 13:01:00"
> 1, "2012-05-24 13:02:00"
> 2, "2012-05-24 13:03:00"
> 2, "2012-05-24 13:04:00"
> 1, "2012-05-24 13:05:00"
> 1, "2012-05-24 13:06:00"
>
> I’m trying to get to a result that flattens the results based on
> source, to look like this:
>
> Source, Stime, Etime
> 1, "2012-05-24 13:00:00","2012-05-24 13:02:00"
> 2, "2012-05-24 13:03:00","2012-05-24 13:04:00"
> 1, "2012-05-24 13:05:00","2012-05-24 13:06:00"
>
> Where Etime is the last Stime for the same source.

How do you figure out that the Etime for (1, 13:00:00) is (1, 13:02:00) and
not (1, 13:01:00)?

Regards,

-- Raj
--
Raj Mathur || raju(at)kandalaya(dot)org || GPG:
http://otheronepercent.blogspot.com || http://kandalaya.org || CC68
It is the mind that moves || http://schizoid.in || D17F

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