Question

I’m having a table with posts. Like (id int, date datetime).
How can I select average posts per day count for each month with one sql request?

Thank you!

Answer 1

This should do it for you:

select month, avg(posts_per_day)
from (select day(date), month(date) as month, count(*) as posts_per_day
      from posts group by 1,2) x
group by 1

Explanation: Because you are doing an aggregate on an aggregate, there is no getting around doing a query on a query:

• The inner query calculates the number per day and captures the month.
• The outer query averages this count , grouping by month.