Question

I’ve got a table with tutorials (tutorial_id,user_id,tutorial_date) and I’m tasked with finding out how many users did a particular number of tutorials.

So, if there were 5 users who did 6 tutorials, and 3 users who did 2 tutorials, I’d want the following output:

Tutorial_Count (unique)            Number of Students With this Tutorial Count
6                                  5
2                                  3

I can get the distinct counts (first column):

SELECT DISTINCT COUNT(user_id) from tutorials group by user_id

But I don’t know how to count the number of users who fit into those count brackets.

Answer 1

Untested, but try this:

;WITH cte AS
(
    SELECT COUNT(user_id) AS Tutorial_Count
    FROM tutorials
    GROUP BY user_id
)
SELECT DISTINCT
    Tutorial_Count,
    COUNT(*) OVER (PARTITION BY Tutorial_Count) AS [Number of Students With this Tutorial Count]
FROM
    cte;