Re: selecting records X minutes apart

My approach would be to add a column for LAST_TS and place a trigger
on insert that populates this new column. Then you have something you
can put in your WHERE clause to test on.

On Fri, Jun 3, 2011 at 12:52 PM, <lists-pgsql(at)useunix(dot)net> wrote:
> I have a table that, at a minimum, has ID and timestamp columns.  Records
> are inserted into with random IDs and timestamps.  Duplicate IDs are allowed.
>
> I want to select records grouped by ID, ordered by timestamp that are X minutes
> apart. In this case X is 5.
>
> Note, the intervals are not X minute wall clock intervals, they are X minute
> intervals from the last accepted record, per-id.
>
> For instance here is some sample input data:
>
> ID      TS (HH:MM)
> -------------------
> 0       20:00
> 1       20:03
> 1       20:04
> 0       20:05
> 1       20:05
> 0       20:08
> 1       20:09
> 0       20:10
>
> I'd want the select to return:
>
> ID      TS (HH:MM)
> -------------------
> 0       20:00
> 0       20:05
> 0       20:10
> 1       20:03
> 1       20:09
>
>
> Does my question make sense?
>
> Thanks in advance,
> Wayne
>
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