How to rank MySQL results, based on different values? - mysql

Question

I have 2 different tables in my database by the name of: rank, settings.
Here is how each table looks like with a few records in them:
Table #rank:
id points userid
-- ----- ------
1 500 1
2 300 2
3 900 3
4 1500 4
5 100 5
6 700 6
7 230 7
8 350 8
9 850 9
10 150 10
Table #settings:
userid active
------ ------
1 0
2 1
3 1
4 1
5 1
6 0
7 1
8 1
9 0
10 1
What I basically want to achieve is to select a specific row from #rank by ID, sort it by points and select 3 rows above the specific ID and 3 row below the specific ID but only for rows where the active column (from #settings) for the user equals 1.
For example:
I would like to select from #rank the ID of 8, and it should return me the following:
rank points userid
---- ----- ------
2 150 10
3 230 7
4 300 2
5 350 8
6 900 3
7 1500 4
I have created quite an extensive query for this, but the problem is, that it is ranking the columns before it decides that the user is active or not. However I need to rank the columns after it is decided that the user is active or not.
SELECT sub2.sort, sub2.points, sub2.userid
FROM
(
SELECT #sort1 := #sort1 + 1 AS sort, puu.points, puu.userid
FROM rank as puu,
(SELECT #sort1 := 0) s
LEFT JOIN
(
settings as p11
)
ON puu.userid = p11.userid,
WHERE p11.active = 1
ORDER BY puu.points DESC
) sub1
INNER JOIN
(
SELECT #sort2:=#sort2+1 AS sort, p2.points, p2.userid
FROM rank as p2,
(SELECT #sort2 := 0) s
LEFT JOIN
(
settings as p12
)
ON p2.userid = p12.userid,
WHERE p12.active = 1
ORDER BY points DESC
) sub2
ON sub1.userid = :userid
AND sub2.sort BETWEEN (sub1.sort - 5) AND (sub1.sort + 5)
Can you guys find any solution for my problem? If you can provide an SQLfiddle demo, that would be really awesome!

Answer 1

SELECT sort, points, user_id, active FROM (
SELECT #pos := #pos + 1 AS sort, id, points, r.user_id, s.active,
IF(user_id = :userid, #userpos := #pos, 0)
FROM rank r
JOIN settings s USING(user_id)
JOIN (SELECT #pos := 0, #userpos := 0) p
WHERE s.active = 1
ORDER BY points DESC
) list
WHERE sort BETWEEN #userpos - 3 AND #userpos + 3
I made a fiddle here: sqlfiddle

Answer 2

Possibly using 2 unioned queries to get the values before the ranking:-
SELECT #rank:=#rank+1 AS rank, points, userid
FROM
(
SELECT id, points, userid
FROM
(
SELECT rank.id, rank.points, rank.userid
FROM rank
INNER JOIN
(
SELECT points
FROM rank
WHERE id = 8
) sub0
ON rank.points >= sub0.points
INNER JOIN settings
ON rank.userid = settings.userid
WHERE settings.active = 1
ORDER BY rank.points LIMIT 3
) sub1
UNION ALL
SELECT id, points, userid
FROM
(
SELECT rank.id, rank.points, rank.userid
FROM rank
INNER JOIN
(
SELECT points
FROM rank
WHERE id = 8
) sub0
ON rank.points < sub0.points
INNER JOIN settings
ON rank.userid = settings.userid
WHERE settings.active = 1
ORDER BY rank.points DESC LIMIT 3
) sub1
) sub2
CROSS JOIN (SELECT #rank:=0) sub3
ORDER BY points