MEDIAN as custom aggregate? - Mailing list pgsql-sql

From Josh Berkus
Subject MEDIAN as custom aggregate?
Date
Msg-id web-146875@davinci.ethosmedia.com
Whole thread Raw
Responses Re: MEDIAN as custom aggregate?  (Masaru Sugawara <rk73@echna.ne.jp>)
List pgsql-sql
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


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