SLQ statement to select only the max values for the given date range - basically which landing pages have had their best ever month *this* month. Change MAX() to MIN() to get the biggest losers.

max_impressions_of_all_time.py

SELECT
  t.landing_page, t.all_impressions
FROM 
  landing_pages_client_v3 AS t
JOIN 
(
  SELECT
    landing_page, 
    MAX(all_impressions) AS max_all_impressions
  FROM landing_pages_client_v3
  GROUP BY landing_page
) AS dt 
  ON dt.landing_page = t.landing_page AND 
     dt.max_all_impressions = t.all_impressions 
WHERE profile_id=565 and
 t.dates >= '2019-01-01 00:00:00' AND
 t.dates < '2019-31-01 00:00:00' limit 5