Question

I am using Mysql and have these tables: (only important columns shown)

Person
id, primary key

Post
id, primary key
points, INT

Visit
id, primary key
person_id, refers to Person
post_id, refers to Post

What I want to find is the Persons (top 5) with most points overall? And the persons with most points on each Post.

Can anyone please guide me? Any help is deeply apreciated!

Answer 1

Top 5 persons with most points overall:

SELECT
    p.id,
    SUM(Post.points) AS total_points
FROM
    Person p
    INNER JOIN Visit v
        ON p.id = v.person_id
    INNER JOIN Post
        ON v.post_id = Post.id
GROUP BY
    p.id
ORDER BY
    SUM(Post.points) DESC
LIMIT 5

Top 5 persons with most points in one post:

SELECT
    p.id,
    MAX(Post.points) AS best_post_points
FROM
    Person p
    INNER JOIN Visit v
        ON p.id = v.person_id
    INNER JOIN Post
        ON v.post_id = Post.id
GROUP BY
    p.id
ORDER BY
    MAX(Post.points) DESC
LIMIT 5

Top 5 posts:

SELECT
    p.id,
    Post.points
FROM
    Person p
    INNER JOIN Visit v
        ON p.id = v.person_id
    INNER JOIN Post
        ON v.post_id = Post.id
ORDER BY
    Post.points DESC
LIMIT 5