CREATE TABLE sensdatas
(
  idserial serial NOT NULL,
  id integer NOT NULL,-- номер устройства
  temperature double precision,-- для функции myparam 0 температура
  pressure double precision,-- для функции myparam 1 давление
  humidity double precision,-- для функции myparam 2 влажность
  sernum integer NOT NULL,
  curenttime timestamp without time zone NOT NULL,
  et integer,
  ep integer,
  eh integer,
  iroom character varying(64),
  CONSTRAINT sensdataskey PRIMARY KEY (idserial)
)

CREATE OR REPLACE FUNCTION public.f_myfunc(
  date1 timestamptz,
  date2 timestamptz,
  interv VARCHAR,
  device INTEGER,
  myparam INTEGER -- 0, 1, 2
)
RETURNS SETOF record AS
$body$
DECLARE
params record;
date_int TIMESTAMP;
BEGIN
date_int=date1;
 
WHILE date_int <= date2 LOOP--цикл по интервалу с шагом "interv"
 
 FOR params IN 
 --выводим среднее значение за "шаг"
IF myparam=0 THEN
 SELECT s.id, s.sernum, avg(s.temperature), date_int FROM sensdatas s
 WHERE s.id=device AND s.curenttime BETWEEN date_int AND date_int + interv::INTERVAL 
 GROUP BY s.id, s.sernum, date_int
 ORDER BY date_int 
 
ELSIF myparam=1 THEN
 SELECT s.id, s.sernum, avg(s.pressure), date_int FROM sensdatas s
 WHERE s.id=device AND s.curenttime BETWEEN date_int AND date_int + interv::INTERVAL 
  GROUP BY s.id, s.sernum, date_int
 ORDER BY date_int
 
ELSIF myparam=2 THEN
 SELECT s.id, s.sernum, avg(s.humidity), date_int FROM sensdatas s
 WHERE s.id=device AND s.curenttime BETWEEN date_int AND date_int + interv::INTERVAL
 GROUP BY s.id, s.sernum, date_int 
 ORDER BY date_int 
 
END IF;
 
 LOOP
 RETURN NEXT params;
 END LOOP;
 
 date_int:=date_int+ interv::INTERVAL;--продвигаемся по интервалу шагом "interv"
 
END LOOP;
 
RETURN;
END;
$body$
LANGUAGE 'plpgsql'
VOLATILE
 
RETURNS NULL ON NULL INPUT
SECURITY INVOKER
COST 100 ROWS 1000;
 
--пример вызова. 3 это номер датчика. 0 это температура
SELECT * FROM f_myfunc(to_timestamp('01.05.2015 10:00:00','dd.mm.yyyy HH24:MI:SS'),
to_timestamp('28.05.2015 16:00:00','dd.mm.yyyy HH24:MI:SS'),'1 hour',3,0)AS(id INTEGER, sernum INTEGER,
pokazateli DOUBLE PRECISION, date_int TIMESTAMP)