Thomas, On Wed, Aug 22, 2012 at 12:25 PM, Thomas Munro <munro@xxxxxxx> wrote: > I noticed that 'avg' works on 'interval', but 'stddev' and 'variance' don't: I don't know why, but you could convert 'interval' into something else where all the functions work: CREATE OR REPLACE FUNCTION interval_to_seconds(interval) RETURNS double precision AS $$ SELECT (extract(days from $1) * 86400) + (extract(hours from $1) * 3600) + (extract(minutes from $1) * 60) + extract(seconds from $1); $$ LANGUAGE SQL; Cheers, Chris -- Christopher Swingley Fairbanks, Alaska http://swingleydev.com/ cswingle@xxxxxxxxx -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general