Query for finding Persons with most points - mysql

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

Answer 2

For each Post
SELECT id FROM Person where id in (SELECT person_id FROM Visit where post_id in
(SELECT id FROM Post order by points DESC limit 5))
Overall (not sure if will work, not tested)
SELECT id FROM Person where id in (SELECT distinct(person_id) FROM Visit where post_id in
(SELECT id FROM Post order by points DESC limit 5) GROUP BY person_id )

Answer 3

SELECT *
FROM
(
SELECT P.id , SUM(PP.points)
FROM PERSON P JOIN VISIT V ON ( V.person_id = P.id )
JOIN POST PP JOIN ON ( PP.id = V.post_id )
GROUP BY P.id
ORDER BY PP.points DESC
)
LIMIT 5;
SELECT *
FROM
(
SELECT P.id , COUNT(*) NUM_OF_POST
FROM PERSON P JOIN VISIT V ON ( V.person_id = P.id )
JOIN POST PP JOIN ON ( PP.id = V.post_id )
GROUP BY P.id
ORDER BY NUM_OF_POST DESC
)
LIMIT 5;