Question

I wonder how the following could be solved with a mysql query, but don’t really know how to proceed past my first count.

In a table there is user ids and an item id they have.

user_id | item
--------------
12      | 1
11      | 3
34      | 1
12      | 2
34      | 2
9       | 1
12      | 3

If I group by user_id and count the user_id, I get a list of users and how many items they have won, like:

user_id | count(user_id) i.e. how many items have they won
-----------------------
9       | 1
11      | 1
12      | 3
34      | 2

How can I in turn count how many users have won 1, 2 or 3 items, ie. count the result of the count, grouped by the count of user_id?

Answer 1

Select from the select:

select times_won, count(*)
from (
    select user_id, count(*) as times_won
    from my_table
    group by 1
) x
group by 1