array_agg() with join question

        timeslot        | pollgrpid |         array_agg          

------------------------+-----------+----------------------------

 2013-05-14 08:58:00-04 |         8 | {1,1,0.00125217437744141}

 2013-05-14 09:00:00-04 |         8 | {1,1,0.000999927520751953}

 2013-05-14 09:02:00-04 |         8 | {1,1,0.00318312644958496}

 2013-05-14 09:04:00-04 |         8 | {1,1,0.000761985778808594}

 2013-05-14 09:06:00-04 |         8 | {1,1,0.000777959823608398}

 2013-05-14 09:08:00-04 |         8 | {1,1,0.101096868515015}

 2013-05-14 09:10:00-04 |         8 | {1,1,0.86168384552002}

 2013-05-14 09:12:00-04 |         8 | {1,1,0.00656795501708984}

 2013-05-14 09:14:00-04 |         8 | {1,1,0.102259159088135}

 2013-05-14 09:16:00-04 |         8 | {1,1,0.000636100769042969}

I wanted to include missing timestamps in my results, so I joined it with generate_series.

SELECT timeslot, pollgrpid, array_agg(outval) 

   FROM 

      ( SELECT generate_series(rrd_timeslot('avail', now() - '58 minutes'::interval), now() + '1 hour'::interval, '2 minutes') AS timeslot ) AS bar 

   LEFT JOIN 

      (SELECT * FROM rrd.a_current WHERE pollgrpid=8 AND timeslot >= now() - '1 hour'::interval AND timeslot <= now() + '1 hour'::interval ORDER BY timeslot, dsnum) AS foo 

   USING(timeslot) 

   GROUP BY timeslot, pollgrpid 

   ORDER BY timeslot;

The array_agg results are reversed.  I had to ODER BY timeslot, dsnum desc on the right of the join to make it match. I am curious as to why this happened.  I am running 9.2.4.

Thanks,

Woody 

iGLASS Networks
www.iglass.net