https://dbfiddle.uk/?rdbms=postgres_9.6&fiddle=047ab5450254f1007677e729d72d341e

postgres-pctDisplay.sql

CREATE OR REPLACE FUNCTION pctDisplay (pct numeric, ch text = '|', length int = 20, includeLabel boolean = TRUE) RETURNS text AS $$
DECLARE x TEXT;
BEGIN
	IF length < 1 OR length > 100 THEN
		length = 20;
	END IF;

	IF pct < 0 THEN
		pct = 0;
	ELSEIF pct > 100 THEN
		pct = 100;
	END IF;

	SELECT ch ||
		rpad(repeat(ch, ((pct / 100) * length)::int - 2), length - 2) ||
		ch ||
		CASE WHEN includeLabel THEN ' ' || round(pct, 1)::text || '%' ELSE '' END
		INTO x;

	RETURN x;
END
$$ LANGUAGE PLPGSQL;