MySQL query to dynamic “Ranking rows”

Question

I\'m having problems running a query ranking. The inner SELECT gives the rows in order of ranking, for each line, the variable @rank increases, if not a position equal to th

Answer 1

First, Thank you all!

I found a way to return the expected result making other selects 2

A) Select first grouped and ordered

SELECT
    SUM( a.value ) AS SUM_VALUES,
    b.id AS b_id,
    b.name AS b_name
FROM
    a INNER JOIN b ON ( a.b_id = b.id )
GROUP BY b.id
ORDER BY SUM_VALUES DESC

B) I do this ranking list

SELECT
    R.*,
   @prev := @curr,
   @curr := R.SUM_VALUES,
   @rank := IF(@prev = @curr, @rank, @rank+1) AS rank
FROM (
        SELECT
            SUM( a.value ) AS SUM_VALUES,
            b.id AS b_id,
            b.name AS b_name
        FROM
            a INNER JOIN b ON ( a.b_id = b.id )
        GROUP BY b.id
        ORDER BY SUM_VALUES DESC
) AS R

C) And lastly, just select what matters

SELECT
    Ranking.b_id,
    Ranking.b_name,
    Ranking.rank
FROM
(
    SELECT
        R.*,
       @prev := @curr,
       @curr := R.SUM_VALUES,
       @rank := IF(@prev = @curr, @rank, @rank+1) AS rank
    FROM (
            SELECT
                SUM( a.value ) AS SUM_VALUES,
                b.id AS b_id,
                b.name AS b_name
            FROM
                a INNER JOIN b ON ( a.b_id = b.id )
            GROUP BY b.id
            ORDER BY SUM_VALUES DESC
    ) AS R
) AS Ranking
WHERE
    Ranking.b_id = 1

The result of this query was:

+------+--------+------+
| b_id | b_name | rank |
+------+--------+------+
|    1 | AAA    |    2 |
+------+--------+------+