Всем доброго дня!

Прошу помощи в написании функции при таком запросе:

это должны быть переменные - ch1,ch2,ГЛ_Q,ГЛ_P,'minute', '2019-01-01 00:00:00' , '2020-01-01 00:00:00'


SELECT dt AS Дата,
COALESCE(ch1, 0) AS ГЛ_Q,
COALESCE(ch2, 0) As ГЛ_P
FROM
(SELECT date_trunc('minute', d.datetime) AS dt,
ROUND(AVG(CASE d.cnlnum WHEN 1 THEN d.val::numeric ELSE NULL END),0) As ch1,
ROUND(AVG(CASE d.cnlnum WHEN 2 THEN d.val::numeric ELSE NULL END),2) As ch2
FROM cnldata AS d WHERE d.cnlnum IN (1,2) AND d.val<> 0
AND datetime BETWEEN '2019-01-01 00:00:00' AND '2020-01-01 00:00:00'
GROUP BY date_trunc('minute', d.datetime)) AS X
ORDER BY dt;