PostgreSQL - sort columns in row

sort-columns-in-row.sql

-- Table: public.testy

-- DROP TABLE public.testy;

CREATE TABLE public.testy
(
  id integer NOT NULL DEFAULT nextval('testy_id_seq'::regclass),
  prod1 integer,
  prod2 integer,
  prod3 integer,
  prod4 integer,
  prod5 integer,
  CONSTRAINT identities_pkey PRIMARY KEY (id)
)
WITH (
  OIDS=FALSE
);

INSERT INTO testy (id, prod1, prod2, prod3, prod4, prod5) VALUES (1, 13, 4, 10, 8, 23);
INSERT INTO testy (id, prod1, prod2, prod3, prod4, prod5) VALUES (2, 4, 5, 1, 8, 12);

SELECT
   unnest(array['prod1', 'prod2', 'prod3', 'prod4', 'prod5']) AS "Values",
   unnest(array[prod1, prod2, prod3, prod4, prod5]) AS "Count"
FROM testy
WHERE id = 1
ORDER BY "Count" DESC
LIMIT 3