MySQL条件计数基于另一列中的值

Question

I have table that looks like this:

id rank
a  2
a  1
b  4
b  3
c  7
d  1
d  1
e  9

I need to get all the distinct rank values on one column and count of all the unique id's that have reached equal or higher rank than in the first column.

So the result I need would be something like this:

rank count
1    5
2    4
3    3
4    3
7    2
9    1

I've been able to make a table with all the unique id's with their max rank:

SELECT 
MAX(rank) AS 'TopRank',
id
FROM myTable
GROUP BY id

I'm also able to get all the distinct rank values and count how many id's have reached exactly that rank:

SELECT
DISTINCT TopRank AS 'rank',
COUNT(id) AS 'count of id'
FROM
  (SELECT 
  MAX(rank) AS 'TopRank',
  id
  FROM myTable
  GROUP BY id) tableDerp
GROUP BY TopRank
ORDER BY TopRank ASC

But I don't know how to get count of id's where the rank is equal OR HIGHER than the rank in column 1. Trying SUM(CASE WHEN TopRank > TopRank THEN 1 END) naturally gives me nothing. So how can I get the count of id's where the TopRank is higher or equal to each distinct rank value? Or am I looking in the wrong way and should try something like running totals instead? I tried to look for similar questions but I think I'm completely on a wrong trail here since I couldn't find any and this seems a pretty simple problem that I'm just overthinking somehow. Any help much appreciated.

Answer 1

One approach is to use a correlated subquery. Just get the list of ranks and then use a correlated subquery to get the count you are looking for:

SELECT r.rank,
       (SELECT COUNT(DISTINCT t2.id)
        FROM myTable t2
        WHERE t2.rank >= r.rank
       ) as cnt
FROM (SELECT DISTINCT rank FROM myTable) r;