To summarize my question at the top, why is it that when I did the JOIN, the array_agg results reversed order?
I had a function that ran the following query: SELECT timeslot, pollgrpid, array_agg(outval) FROM (SELECT * FROM rrd.a_current WHERE pollgrpid=8 ORDER BY timeslot, dsnum) AS foo WHERE timeslot >= now() - '1 hour'::interval AND timeslot <= now() + '1 hour'::interval GROUP BY timeslot, pollgrpid ORDER BY timeslot; 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; timeslot | pollgrpid | array_agg ------------------------+-----------+---------------------------- 2013-05-14 09:02:00-04 | 8 | {0.00318312644958496,1,1} 2013-05-14 09:04:00-04 | 8 | {0.000761985778808594,1,1} 2013-05-14 09:06:00-04 | 8 | {0.000777959823608398,1,1} 2013-05-14 09:08:00-04 | 8 | {0.101096868515015,1,1} 2013-05-14 09:10:00-04 | 8 | {0.86168384552002,1,1} 2013-05-14 09:12:00-04 | 8 | {0.00656795501708984,1,1} 2013-05-14 09:14:00-04 | 8 | {0.102259159088135,1,1} 2013-05-14 09:16:00-04 | 8 | {0.000636100769042969,1,1} 2013-05-14 09:18:00-04 | 8 | {0.000638008117675781,1,1} 2013-05-14 09:20:00-04 | 8 | {0.174574136734009,1,1} 2013-05-14 09:22:00-04 | 8 | {0.1006920337677,1,1} 2013-05-14 09:24:00-04 | 8 | {0.00069117546081543,1,1} 2013-05-14 09:26:00-04 | 8 | {0.114289045333862,1,1} 2013-05-14 09:28:00-04 | 8 | {0.116230010986328,1,1} 2013-05-14 09:30:00-04 | 8 | {0.0349528789520264,1,1} 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