In MySQL I need to retrieve artist with highest points by location - php

Question

In MySQL I need to get artist with highest points by location. Please help.
user_location_tbl (user location table)
|--------------------------------------|
| countryLat | countryLong | userid |
|--------------------------------------|
| 31.695766 | 54.624023 | 1 |
| 20.593684 | 78.96288 | 2 |
| 20.593684 | 78.96288 | 3 |
| 20.593684 | 78.96288 | 4 |
| 31.695766 | 54.624023 | 5 |
|--------------------------------------|
fans_table (to view which artist has which user as a fan)
|----------------------|----------
| artist_id | user_id | Points |
|----------------------|----------
| 1 | 1 | 20 |
| 1 | 2 | 30 |
| 2 | 1 | 40 |
| 2 | 3 | 40 |
| 3 | 1 | 60 |
|----------------------|----------
artist_table (list of artist)
|-------------------|
| artistid | name |
|-------------------|
| 1 | raja |
| 2 | sekar |
| 3 | thomas |
|-------------------|
I need to get location wise which artist is having highest point but I can't do it in a single query. If I put sum(points) and group by countryLat, countryLong, artistid, I get the following result...
|---------------------------------|
| 100 | 20.593684 | 78.96288 | 1 |
| 50 | 20.593684 | 78.96288 | 2 |
| 100 | 31.695766 | 54.624023 | 3 |
| 90 | 31.695766 | 54.624023 | 1 |
|---------------------------------|
...but I only need the artist with highest point on that location as in the example below...
|---------------------------------|
| 100 | 20.593684 | 78.96288 | 1 |
| 100 | 31.695766 | 54.624023 | 3 |
|---------------------------------|
SQL
SELECT Sum(c.tot_points),
a.artist_id
FROM `fans_table` AS a
INNER JOIN `user_location_tbl` AS b
ON a.user_id = b.user_id
INNER JOIN artist_table AS c
ON a.artist_id = c.id
GROUP BY b.countrylat,
b.countrylong,
a.artist_id
Above is my query

Answer 1

So assuming I understand your question right you want to get which artist has the most points for each location so this would be the process to figure it out manually:
// First we add up all the points for each artist in each location:
|----------------------------------------------|
| Points | countryLat | countryLong | artistid |
|----------------------------------------------|
| 30 | 20.593684 | 78.96288 | 1 |
| 40 | 20.593684 | 78.96288 | 2 |
| 0 | 20.593684 | 78.96288 | 3 |
| 20 | 31.695766 | 54.624023 | 1 |
| 40 | 31.695766 | 54.624023 | 2 |
| 60 | 31.695766 | 54.624023 | 3 |
|----------------------------------------------|
// Then we get the max for each location
|----------------------------------------------|
| Points | countryLat | countryLong | artistid |
|----------------------------------------------|
| 40 | 20.593684 | 78.96288 | 2 |
| 60 | 31.695766 | 54.624023 | 3 |
|----------------------------------------------|
The query to do this is as follows
SELECT artist_id, ul.countryLat, ul.countryLong, max_points
FROM fans_table f
JOIN user_location_tbl ul
ON ul.userid = f.user_id
JOIN (
SELECT countryLat, countryLong, MAX(f.total_points) max_points
FROM
(SELECT artist_id, countryLat, countryLong, SUM(Points) as total_points
FROM fans_table f
JOIN user_location_tbl ul
ON ul.userid = f.user_id
GROUP BY artist_id, countryLat, countryLong) f
GROUP BY countryLat, countryLong) p
ON p.countryLat = ul.countryLat
AND p.countryLong = ul.countryLong
GROUP BY f.artist_id, ul.countryLat, ul.countryLong
HAVING p.max_points = SUM(Points)

Answer 2

Making an assumption that the points in an area will be unique (ie, either there won't be 2 equally popular artists in an area, or if there are you want them both) then something like the following will do it
SELECT Sub3.artist_id, Sub3.countryLat, Sub3.countryLong, Sub2.MaxArtistLocalPoints
FROM
(
SELECT a.artist_id, countryLat, countryLong, SUM(a.Points) AS ArtistLocalPoints
FROM `fans_table` AS a
INNER JOIN `user_location_tbl` AS b ON a.user_id=b.user_id
INNER JOIN artist_table AS c ON a.artist_id=c.id
GROUP BY a.artist_id, countryLat, countryLong
) Sub3
INNER JOIN
(
SELECT countryLat, countryLong, MAX(ArtistLocalPoints) AS MaxArtistLocalPoints
FROM
(
SELECT a.artist_id, countryLat, countryLong, SUM(a.Points) AS ArtistLocalPoints
FROM `fans_table` AS a
INNER JOIN `user_location_tbl` AS b ON a.user_id=b.user_id
INNER JOIN artist_table AS c ON a.artist_id=c.id
GROUP BY a.artist_id, countryLat, countryLong
) Sub1
) Sub2
ON Sub3.countryLat = Sub2.countryLat
AND Sub3.countryLong = Sub2.countryLong
AND Sub3.ArtistLocalPoints = Sub2.MaxArtistLocalPoints