check leap year or not in PostgreSQL

How to check the given year is leap year or not in PostgreSQL.?

I tried below query.But it is showing error message.

select extract(year from hiredate)% 4 = 0 from emp

You must cast the extracted year to an integer.

select extract(year from hiredate)::integer % 4 = 0 from emp

However, that is the incorrect formula for a leap year. It is Every four years except every 100 except every 400. 1900 was not a leap year, but 2000 was.

create function is_leap_year(timestamp)
returns boolean as $$
declare y integer;
begin
  y := extract(year from $1);
  return (y % 4 = 0) and (y % 100 <> 0 or y % 400 = 0);
end
$$ language plpgsql;

Alternatively, you can check to see what day comes before March 1st in that year. This is safer as it will use Postgresql's internal logic.

create function is_leap_year(timestamp)
returns boolean as $$
begin
  return date_part(
    'day',
    make_date(date_part('year', $1)::int, 3, 1) - '1 day'::interval
  ) = 29;
end
$$ language plpgsql;