Postgres time_ago_in_words(date) function

Postgres time_ago_in_words(date) function

CREATE OR REPLACE FUNCTION time_ago_in_words(timestamp with time zone)
RETURNS text
LANGUAGE SQL
AS $$
  SELECT CASE
  WHEN date_part('year', age(current_timestamp, $1)) = 1 THEN concat(date_part('year', age(current_timestamp, $1)), ' year ago')
  WHEN date_part('year', age(current_timestamp, $1)) > 1 THEN concat(date_part('year', age(current_timestamp, $1)), ' years ago')
  WHEN date_part('month', age(current_timestamp, $1)) = 1 THEN concat(date_part('month', age(current_timestamp, $1)), ' month ago')
  WHEN date_part('month', age(current_timestamp, $1)) > 1 THEN concat(date_part('month', age(current_timestamp, $1)), ' months ago')
  WHEN date_part('day', age(current_timestamp, $1)) = 1 THEN concat(date_part('day', age(current_timestamp, $1)), ' day ago')
  WHEN date_part('day', age(current_timestamp, $1)) > 1 THEN concat(date_part('day', age(current_timestamp, $1)), ' days ago')
  WHEN date_part('hour', age(current_timestamp, $1)) = 1 THEN concat(date_part('hour', age(current_timestamp, $1)), ' hour ago')
  WHEN date_part('hour', age(current_timestamp, $1)) > 1 THEN concat(date_part('hour', age(current_timestamp, $1)), ' hours ago')
  WHEN date_part('minute', age(current_timestamp, $1)) <= 1 THEN concat(date_part('minute', age(current_timestamp, $1)), ' minute ago')
  WHEN date_part('minute', age(current_timestamp, $1)) > 1 THEN concat(date_part('minute', age(current_timestamp, $1)), ' minutes ago')
  END;
$$;