Computes the average amount of points of comments per month.

bigqueryhnpts-comments.sql

SELECT
  CONCAT(STRING(YEAR(time_ts)),'-',RIGHT(STRING(100 + MONTH(time_ts)), 2)) AS Month,
  AVG(ranking) AS rank,
  EXACT_COUNT_DISTINCT([by]) AS CommentSum,
  AVG(ranking) / EXACT_COUNT_DISTINCT([by]) AS PerCapita
FROM
  [bigquery-public-data:hacker_news.comments]
GROUP BY
  1
ORDER BY
  1;