percent.sql

-- The args being numeric cause auto casting; This is what we want
-- e.g `COUNT(*)` returns a whole number but we often want to divide it to float
-- Postgres percent function

CREATE OR REPLACE FUNCTION percent(portion numeric, total numeric, round_level integer default 1)
RETURNS numeric
IMMUTABLE
RETURNS NULL ON NULL INPUT
PARALLEL SAFE
as $fbd$
    select
        CASE
        WHEN total = 0 THEN 0
        ELSE ROUND(100 * (portion / total), round_level)
        END
$fbd$ language sql;