Thanks to all .... I had a tickling feeling at the back of my mind that there was a neater answer here. For the record, times (all from in-memory cached data, averaged over a bunch of runs):
Dependent subquery = 117.9 seconds Join to temp table = 2.7 sec DISTINCT ON = 2.7 sec So the DISTINCT ON may not be quicker, but it sure is tidier. Cheers Dave On Thu, Feb 24, 2011 at 2:24 PM, Kevin Grittner <kevin.gritt...@wicourts.gov > wrote: > Michael Glaesemann <g...@seespotcode.net> wrote: > > > SELECT DISTINCT ON (data.id_key) > > data.id_key, data.time_stamp, data.value > > FROM data > > ORDER BY data.id_key, data.time_stamp DESC; > > Dang! I forgot the DESC in my post! Thanks for showing the > *correct* version. > > -Kevin >
