Can't you do something like select age from ages order by age limit 1 offset (select count(*) from ages)/2;
except you can't nest the select so you'll have to use a variable to hold it... Make sure it does the right thing when there is an odd number of rows. I don't understand why you want the median and not some parameters of your assumed distribution (mean and variance, for example) but each to his own... Allan. Josh Berkus wrote: > Folks, > > Hey, anybody have a custom aggregate for median calucation? I'm doing > this through a PL/pgSQL function, and a custom aggregate would probably > be faster. > > For those whose stats terminology is rusty, the "median" is the "middle" > value in a distribution. For example, if we had the following data: > > Table ages > person age > Jim 21 > Rusty 24 > Carol 37 > Bob 62 > Leah 78 > > Our Median would be Carol's age, 37. This is a different figure from > the Mean, or Average, which is 44.4. Using the combination of the Mean > and the Median you can do all kinds of interesting statistical analysis. > > -Josh Berkus > > ______AGLIO DATABASE SOLUTIONS___________________________ > Josh Berkus > Complete information technology [EMAIL PROTECTED] > and data management solutions (415) 565-7293 > for law firms, small businesses fax 621-2533 > and non-profit organizations. San Francisco > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
