postgresql 自定义聚合函数

CREATE OR REPLACE FUNCTION public.sfun_test1(
    results numeric[],val numeric)
    RETURNS numeric[]
    LANGUAGE ‘plpgsql‘

    COST 100
    VOLATILE 
AS $BODY$

BEGIN
    results :=array_append(results,val);
RETURN results;
END;
$BODY$;

ALTER FUNCTION public.sfun_test1(numeric[],numeric)
    OWNER TO postgres;

CREATE OR REPLACE FUNCTION public.sffun_test1(
    results numeric[])
    RETURNS numeric
    LANGUAGE ‘plpgsql‘

    COST 100
    VOLATILE 
AS $BODY$
DECLARE 
    ppp integer;--百分位指标
    kkk numeric;--序号
    sss integer;--序号
    ret numeric[];--结果
BEGIN
    ppp=90;--第90百分位
    kkk=1+(array_length(results,1)-1)*ppp/100::numeric;
    sss=floor(kkk);

    ret=array_sort(results,‘asc‘);

RETURN ret[sss]+(ret[sss+1]-ret[sss])*(kkk-sss);
END;
$BODY$;

ALTER FUNCTION public.sffun_test1(numeric[])
    OWNER TO postgres;

CREATE AGGREGATE agg_test1(
BASETYPE = numeric,SFUNC = sfun_test1,STYPE = numeric[],FINALFUNC = sffun_test1
);