Querying DAU/MAU over time (daily)

Question

I have a daily sessions table with columns user_id and date. I\'d like to graph out DAU/MAU (daily active users / monthly active users) on a daily basis. For example:

Answer 1

Assuming you have values for each day, you can get the total counts using a subquery and range between:

with dau as (
      select date, count(userid) as dau
      from dailysessions ds
      group by date
     )
select date, dau,
       sum(dau) over (order by date rows between -29 preceding and current row) as mau
from dau;

Unfortunately, I think you want distinct users rather than just user counts. That makes the problem much more difficult, especially because Postgres doesn't support count(distinct) as a window function.

I think you have to do some sort of self join for this. Here is one method:

with dau as (
      select date, count(distinct userid) as dau
      from dailysessions ds
      group by date
     )
select date, dau,
       (select count(distinct user_id)
        from dailysessions ds
        where ds.date between date - 29 * interval '1 day' and date
       ) as mau
from dau;