Re: need to join successive log entries into one

On Wed, 14 Mar 2001, you wrote:
> On 3/14/01, 5:24:12 PM, George Young <gry(at)ll(dot)mit(dot)edu> wrote regarding [SQL]
> I need to join successive log entries into one:
> > I have a table like:
>
> > run | seq | start | done
> > 1415| 261| 2001-01-29 12:36:55| 2001-02-07 13:02:38
> > 1415| 263| 2001-02-14 07:40:04| 2001-02-15 16:05:04
> > 1415| 264| 2001-02-16 16:05:05| 2001-03-08 16:34:03
> > 1415| 265| 2001-03-08 16:34:04|
>
> > This is a log of some operations done on some runs. 'seq' is the step
> > within the run.
>
> > I need to produce a new table that coalesces immediately successive
> > operations on a run into one, e.g.:
>
> > run | start | done
> > 1415| 2001-01-29 12:36:55| 2001-02-07 13:02:38
> > 1415| 2001-02-14 07:40:04|
> > 1747| 2001-02-15 09:14:39| 2001-03-01 09:02:39
> > 1747| 2001-03-05 13:13:58|
> > 1954| 2001-02-02 20:55:39| 2001-03-02 10:17:15
>
> Try:
>
> select run,min(start),max(done) from mytable group by run;

Alas, this combines *all* entries for a given run, not just those that
are imediately adjacent (in time, or by 'seq' number)...

--
George Young, Rm. L-204 gry(at)ll(dot)mit(dot)edu
MIT Lincoln Laboratory
244 Wood St.
Lexington, Massachusetts 02420-9108 (781) 981-2756