Hello,
I've defined a function to calculate standard deviation of angular
values:
CREATE AGGREGATE public.stddev(angle_vectors) (
SFUNC=array_append,
STYPE=angle_vectors[],
FINALFUNC=angle_vectors_stddev_yamartino
);
The type angle_vectors is simply an array:
CREATE TYPE public.angle_vectors AS
(x double precision,
y double precision);
COMMENT ON TYPE public.angle_vectors
IS 'This type holds the x (sine) and y (cosine) components of angle(s).';
How can I protect this function so that NULL is returned whenever *all*
input rows are NULL?
Thanks for any feedback,
--
Seb
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