Question

I have these 2 tables

categories with fields “id, category, total”
users with fields “id, category_id, title”

Category is a list of categories that a user can select.
Every time a user pick a certain category, we increment the total counter. (i.e popularity)

How can I grab a unique user data per category based ordered by categories.total and also the user.id needs to be the latest?

This is what I have. Almost there except this grabs the first user id.

select users.id from users left join categories on users.category_id = categories.id group by users.category_id order by categories.total desc

To illustrate, here is an example:
categories table has the following values
id = 1, category = free, total = 3
id = 2, category = expensive, total = 1
id = 3, category = cute, total = 2

users table has the following values
id = 1, category_id = 1, title = aello
id = 2, category_id = 2, title = bello
id = 3, category_id = 3, title = zello
id = 4, category_id = 1, title = gello
id = 5, category_id = 3, title = cello
id = 6, category_id = 1, title = fello

The sql query that I have returns the following users: 1, 3, 2 (the first user to be associated with the category that has the most total)

However, what I want the result to be is: 6, 5, 2 (the LAST user to be associated with the category that has the most total)

Thanks,
Tee

Answer 1

Your requirements confuse me… so I’m not sure if this will really accomplish what you want… but it should return (6,5,2) (in no particular order). Add “ORDER BY category_id” or something, if ordering is important.

SELECT MAX(id)
FROM users
GROUP BY category_id;

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To address your comment, try this (untested, as I don’t have MySQL installed anywhere):

SELECT *
FROM users
WHERE id = (
    SELECT MAX(id)
    FROM users
    GROUP BY category_id
);