CREATE OR REPLACE FUNCTION public.last_day(timestamp without time zone)
 RETURNS date
 LANGUAGE sql
 IMMUTABLE STRICT
AS $function$
  SELECT CASE
    WHEN EXTRACT(MONTH FROM $1) = 12 THEN
      (((EXTRACT(YEAR FROM $1) + 1) operator(pg_catalog.||) '-01-01')::date - INTERVAL '1 day')::date
    ELSE
      ((EXTRACT(YEAR FROM $1) operator(pg_catalog.||) '-' operator(pg_catalog.||) (EXTRACT(MONTH FROM $1) + 1) operator(pg_catalog.||) '-01')::date - INTERVAL '1 day')::date
    END
$function$