Question

I have 3 tables – News, Content and Edits.

Every row in each table contains a user_id field.

What I want to do is make a list of the top contributors to these 3 tables.

So I need to count how many times each different user_id appears in each table and order from the highest count to the lowest.

Answer 1

Like this:

SELECT 
    user_id,
    COUNT(*) AS all_actions 
FROM (
    SELECT user_id FROM News
    UNION ALL
    SELECT user_id FROM Content
    UNION ALL
    SELECT user_id FROM Edits
) tmp_table
GROUP BY user_id
ORDER BY all_actions DESC