How to calculate DAU/MAU with BigQuery (engagement)

Question

DAU and MAU (daily active users and monthly active users) are an established way of measuring user engagement.

How can I get these numbers using SQL and Google BigQ

Answer 1

In order to analyze trends while not waiting to have "full month", there is a need to look at each day with its predecessor 30 days... I am afraid that the suggested solution (by Felipe Hoffa), changes the question, not just the data retrieval query.

You can find bellow my take of the issue. I am not sure what it does under the hood in terms of performance, and it is not very fast (much slower than Felipe's...), but it covers the business need as I understand it. Still, if you could offer a solution that optimize this approach, that would be great.

Please note: no use of any joins and sub aggregates, just splits, group by, and date manipulations.

SELECT
  *,
  DAU/WAU AS DAW_WAU,
  DAU/MAU AS DAW_MAU,
FROM (
  SELECT
    COALESCE(DAUDate,WAUDate,MAUDate) AS ReportDate,
    subreddit,
    EXACT_COUNT_DISTINCT(IF(DAUDate IS NOT NULL,author,NULL)) AS DAU,
    EXACT_COUNT_DISTINCT(IF(WAUDate IS NOT NULL,author,NULL)) AS WAU,
    EXACT_COUNT_DISTINCT(IF(MAUDate IS NOT NULL,author,NULL)) AS MAU,
  FROM (
    SELECT
      DDate,
      subreddit,
      author,
      Ind,
      DATE(IF(Ind=0,DDate,NULL)) AS DAUDate,
      DATE(IF(Ind<7,DATE_ADD(DDate,Ind,"Day"),NULL)) AS WAUDate,
      DATE(IF(Ind<30,DATE_ADD(DDate,Ind,"Day"),NULL)) AS MAUDate
    FROM (
      SELECT
        DATE(SEC_TO_TIMESTAMP(created_utc)) AS DDate,
        subreddit,
        author,
        INTEGER(SPLIT("0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30",",")) AS Ind
      FROM
        [fh-bigquery:reddit_comments.2015_09],
        [fh-bigquery:reddit_comments.2015_08] ))
  WHERE
    COALESCE(DAUDate,WAUDate,MAUDate)50000
ORDER BY
  2,
  1 DESC