TIL - 250129

URL : https://datalemur.com/questions/sql-average-post-hiatus-1

SELECT
  user_id
  ,EXTRACT(DAY FROM MAX(post_date) - MIN(post_date)) 
FROM posts
WHERE EXTRACT(YEAR FROM post_date) = 2021
GROUP BY user_id
HAVING COUNT(post_id) > 1
;

URL : https://datalemur.com/questions/completed-trades

SELECT 
  city
  ,count(user_id) total_orders
FROM trades td
INNER JOIN users ur 
USING (user_id)
WHERE status = 'Completed'
GROUP BY 1
ORDER BY 2 DESC
LIMIT 3
;