URx

DECLARE
  lInt INTEGER;
  lArr INTEGER[];
BEGIN
  IF array[lInt] <@ lArr THEN
    ..
  END IF;
END

CREATE TABLE foo (c1 INTEGER, c2 text);
INSERT INTO foo
  SELECT i, md5(random()::text)
  FROM generate_series(1, 1000000) AS i;

DELETE FROM wgdump.dump WHERE ctid NOT IN (
	SELECT MAX(ctid) FROM wgdump.dump GROUP BY ts
);